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Fen End Pit

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Blog Entries posted by Fen End Pit

  1. Fen End Pit
    First up the results of my attempts to cut a mitre joint with a laser cutter. My jig worked pretty well but it was very time consuming to get the part on the jig correctly and to align the laser to where I wanted the cut to be. The biggest problem is that the 'red dot' is only really a rough guide for where the laser will cut and it isn't actually in the same place. It is good enough to spot whether the job fits the material when you press 'test' but not really up for fine alignment.
     

     
    The resulting joint line isn't too bad but I suspect not up to job of hiding a corner completely. I'll try it with again with a couple of the parts which have bricks engraved on them and see how that looks.
     

     
    Next we have a demonstration of what happens when you get the power to high! It didn't look too bad as it was cutting....
     

     
    However turning it over demonstrates the problem!
     

     
    you can see that the brick engrave lines almost went all the way through, oops. Might be good for modelling the WDLR though!
     

     
    Finally how it is meant to be done. Now to just write down those settings for the different cuts. If anything I could probably reduce the power of the engrave lines still further. Currently I get a depth of about 1mm in the 3mm MDF.
     

     
    Still it is all an interesting learning curve and with the size of the things I'm cutting 3mm MDF isn't exactly the most expensive material to waste.
     
    David
  2. Fen End Pit
    On the advice of the honourable member of Litlington I took a look at the website of KK Produkcja Mikroantriebe in Poland. http://www.shop.kkpmo.com/ and purchased a frankly tiny motor and gearbox. The motor is obviously one from a phone and is 6mm in diameter the 80:1 gearbox takes the overall length of the unit to a massive 22mm! The unit was tested at takes about 4v to reach maximium speed, this shouldn't be a problem as I can limit the voltage using the DCC decoder which I'm going to have to squeeze in somewhere.
     

     
    I've had to trim the 1mm axle down to length a bit and have also realised that I have a problem as the foot boards are very close together to fit P4 wheels between. I'm certainly going to have to do something pretty serious with the width of the N gauge wheels provided in the kit as with them at the thickness they currently are I'm never going to be able to fit them in.
     

     
    I'm quite pleased with how little the unit is going to project into the 'cab'. Bear in mind that there is a seat going across this I thick a small pile of tarpaulin and the gangers' lunch should be able to hide it.
     

     
    Put together with the trolley I think this has the potential to be a small but eye-catching addition to my layouts stock.
     

     
    I expect the next step is to make some kind of paxoline base as a chassis and then work out how I'm going to get the wheels to fit on the 1mm shaft. I beginning to think that taking the tyres off the wheels, turning them down and then making a new tufnol centre may be the way to go.
     
    David
  3. Fen End Pit
    Santa, assisted by the elves at Kernow Models, brought me a Derby Lightweight for Christmas. (My family are good an knowing just what I want). Also delivered came a set of conversation wheels from Branchlines.
     
    So last Friday night the two presents were put together and by the end of the evening the unit was making jaunts up and down a Midland branch in South Cambridgeshire (thanks Brian!). More suited perhaps to East Anglian branchlines that Empire Basin's north London but that is the way my mind is leaning at the moment.
     

     
    Also in the post all the way from Poland came a tiny motor and gear box which is intended to go into my Wickham trolley. I'm going to need to do something a bit clever to go from the 1mm axle of the unit up to the axle diameter of the N gauge wheels but that'll be a challenge to keep me quiet for a few weeks.
     
    Happy New Year everybody.
     
    David
  4. Fen End Pit
    Having fitted track on two levels I thought I'd better get some power back on and make sure I could still drive trains round and round. This hasn't been possible since the original fiddleyard was removed in February. I wasn't happy with the idea of just feeding power to all the levels all the time as this seemed like a recipe for disaster. I could just imagine selecting the wrong loco on the DCC and then driving it off the top level when it wasn't aligned with the exit track! The solution I've adopted is to feed the power to each level through a microswitch which is only closed when the level is aligned with the layout. You can just make out the rollers of these on the photo together with the little bent rail device which activates them.
     

     
    It has been really good to be able to see some trains run again and I'm enjoying the extra 10cm in fiddleyard length which makes certain combinations vehicles possible where it wasn't previously. So my Claud can now haul 3 Mk1s around AND fit in the fiddleyard.
     
    Inspired I must now get on fitting the next level, though Maplin have run out of micro switches with rollers so I've got to wait a few days until they get some more. I could have got them from Rapid Electronics considerably cheaper but didn't have enough to justify the P&P.
     
    David
  5. Fen End Pit
    The little grey cells (and Turbocad) have been working since my last posting. The limitations of the space result in a basic track layout which is quite similar to Empire Basin. Using Templot has resulted in a much smoother flow of track work and it is interesting to see that the single slip ends up about 2 inches longer than my original version.
     

     
    The biggest change is the design of the baseboards. You'll see I now have 4 conventional baseboards for the scenic area, with all of the difficult trackwork confined to the two centre boards. The right-hand board can slide slightly into the window to make space to separate the boards and then flip them up onto their backs to work ok. I'm thinking of using some 9 or 12mm ply and framing with say 3" deep ply lengths.
     
    The location is now more rural than Empire Basin, I'm thinking Essex/Suffolk border but I'm probably going to cherrypick a few scenes from most of Ian Allen's travels! Starting on the left you have the slightly unusual arrangement of an overbridge with a station building and the platforms extending under the bridge. The building I've drawn up is based on Reedham in Norfolk and fits quite well. This arrangement gives me a visible reason for trains to stop without having to model an entire platform! To the rear of the track is a small water tower which provides water for the station's water crane. (need suitable GER prototype). Moving along there is an end loading dock and cattle dock with the entrance from the station access road.
     
    A cross-over is provided which also features a slip into a goods loop (exactly as I had on Empire Basin but the loop is shorter) and there is a trailing access to a small goods yard. A double slip gives access to the cattle dock. The yard will feature a coal siding and also allow a train to be 'put inside' to clear the main line. The siding is the same length as the fiddleyard so that I can find a whole train.
     
    To the rear on the right hand side is a small mill/maltings/cyder factory which will require regular traffic of vans, coal and grain wagons. I have a growing collection of unfeasibly small industrial locomotives (Barclay fireless, Ruston 48DS etc) which may well get used to shunt the sidings! Whether the wagon turntables will work is still to be decided.
     
    The station signal box is at the end of the loop and is situated here so that the signalman can control the gates of the level crossing over the lane. This will be one of those GER level crossings with single long gates and huge gate posts with tie rods down to the gates. On the far right hand side the line curves to cross a slow wide river (lots of reeds) on a slightly patched up trestle bridge. (think St Ives/Godmanchester). The speed restriction gives the viewer plenty of time to admire the light flashing between the spokes of the wheels. On the bank next to the road will be a couple of small buildings, may be a pub ('The Ferryboat')?
     
    The vertical fiddleyard remains in place.
     
    So that is the plan for now, I'd welcome your comments, ideas for prototype buildings etc.
     
    Empire Basin is still in place, I've not done anything destructive yet!
     
    thanks
    David
  6. Fen End Pit

    Loco weighbridge

    By Fen End Pit,

    This will probably appaul the continuous springy beam folks but when you have individual springs on a chassis it is important to be able to adjust them so that the effective weight on each wheel is similar. I had some problems with my J39 which would hold the track then 'turning right' but not 'turning left'. It was suggested that perhaps the springing on the front axle was uneven so I decided to build a rig to try and check this out.
     
    An £7 set of electronic scales was purchased off ebay (I'm still expecting a raid from the drug squad as I'm sure this is the only other use for this sort of thing) and then a weigh bridge formed for brass square tube was soldered up. The tube sits over the scales with a moving section which supports one wheel only on the balance plate of the scales. This allowed me to confirm that there was indeed a 20g difference between the left and right hand fron wheel. A tweak to adjust the spring end-stops on the Bradwell chassis and things are much better.
     

     

     
    The D16/3 is now in black, maybe post a picture later.
     
    David
  7. Fen End Pit
    So, having declared that the layout was 'back on track' in my last posting I then didn't put anything on the blog for another six months, what has been going on? To be honest, not much; modelling has been pretty much confined to my usual Friday nights out with practically nothing going on between one week and the next. Some of the reason for this has been practical but most has just been down to not being 'in the mood'. I'm sure most people get those times when they look at a modelling project, imagine what they would like it to look like and then think, 'if I wanted to get there I wouldn't start from here'. Probably the 'kiss of death' was a PM from the editor of the Scalefour News asking for some words about the layout.
     
    Looking at where I had got to I have come to several unpleasant conclusions the most critical of which is that the basic infrastructure I built for the layout almost five years ago just isn't up to the job. I have found myself not wanting to progress on the scenics because the boards were not designed to allow easy access to work on the mechanics and electrics underneath. The main layout base was a shelf of 15mm MDF on some spur shelving and the viaduct section and other areas of the layout were built as 'jigsaw' pieces which sit onto the shelf. The result is lots of odd-shaped boards with lots of joints between them. These boards are then difficult to separate and impossible to 'put on their backs' to work on anything underneath. With the benefit of hindsight what I should have done is build more conventional board sections which could be separated and then flipped up on their backs for access. The nature of my modelling means that I often have several goes at building things, my interest in electronics for example has meant that several major redesigns in the wiring have taken place as my experience and the tools available from the MERG have developed.
     
    So, I'm beginning to come to the conclusion that Empire Basin may well get redeveloped. I'm looking at the bits of the layout work, ideas that mostly worked but I'd like to have another go at doing better and what things were just bad ideas in the first place. The double track secondary main line is going to stay. The vertical fiddleyard to save space will be mostly unchanged. I think I will abandon the lower level section and the steep gradients to get there as Alex Jackson couplings and changes in gradients are a recipe for heart-ache.
     
    So, the closure notices are up, the public inquiry has started and the permanent way team have taken delivery of a new vehicle.
     

     
    It will come in handy to move the gas axe around when the time comes. I'm not intending to do anything really major for a few months. I've been putting a few ideas together in Templot which are slowly coming together.
     
    On a more positive note I've also signed up as a founder member for Cambridge Makespace http://makespace.org/ who are setting up a public workspace with access to various tools I've been wanting to try for several years but could never justify (3D printers, CNC milling machine, laser cutter etc.) I'm really rather excited about getting access to these kind of facilities. The 'hackspace' movement http://hackspace.org.uk/view/Main_Page is slowly taking hold in the UK with a fair few similar organisations springing up in major city across the country. It will be interesting to see what use of these the model railway community make.
     
    David
  8. Fen End Pit

    MERG DCC system

    By Fen End Pit,

    I thought folks might be interested in a couple of photographs of the new MERG CBUS based DCC system. This uses a CANBUS (originally developed for the automotive industry) to transmit the signals from the handset to the command station which then generates the completely standard DCC signals on the track. The advantage is that this is the same wiring bus as I using for controlling the rest of the layout using other MERG CBUS boards. Ultimately I should be able to run the whole layout with 6 to 8 wires between the boards.
    Two for the DCC signal.
    Two for the CBUS.
    Two for a 12v DC pair to power the modules.
    I'll probably end up with another pair for a 16AC as this can then be used if I need power anywhere else.

    There are three components to the DCC system, A command station which is a simple PCB costing around £25 to build, a number of handsets which are available as a kit for £38 and a soon to be released booster which will be another ~£25. Without the booster you are limited to pulling about 1.5amps in total but that is proving adequate to run a couple of trains around Empire Basin with no problems.
     
     
    The command station is pretty straight-forward to build being just a single board and convention 'through hole' mounting of components. As usually you need to take some care with your soldering and reading the instructions but it isn't beyond the skills of a beginner.
     

     
    The handset on the other hand is a good deal more complex requiring the use of surface mount components. These look a bit scary to start off with and I watched several video clips on Youtube demonstrating how to solder a chip with 20 pins down one side an inch long onto a board with trepidation before having a go. In the end I found it wasn't as bad as I feared, a combination of a circuit board covered with a solder resistant surface (except that is where you need to solder!) and the smallest soldering iron bit Maplins had did the trick. I also bought some de-soldering wick which came in handy on the occasion when I did manage to bridge a connection. In the end the little handset really does feel like a quality part and is a credit to those involved with the design. The knob is positioned nicely for the thumb and you can easily drive the loco with one hand. The push buttons are very easy to work and the typical operations of selecting a loco or turning a function on and off are all quite logically and take very little getting used to. There are a couple of limitations with the current version of the firmware around taking control of a loco already assigned to another handset but these are all developments due in forthcoming releases.
     

     
    A combination of the MERG command station, the CAN-USB interface which allows a PC to talk to the CBUS and the Java Model Railway Interface (JMRI) also allows the use of an Android phone or (if you want to sell your soul to Apple) a Iphone as a throttle. I'm tempted, but not tempted enough to want to part with the cost of a loco kit just to try it!
     
    David
  9. Fen End Pit
    It has, as they say, been a while since the last blog entries. What with the unexpected appearance at the Ely show with 'Fen End Pit' and biggest son doing AS levels and wanting help revising Empire Basin has taken a bit of a back seat. To be honest I was a bit dissatisfied with the operation and reliablity of the vertical fiddleyard and it was a bit of a downer.
     
    The problem was that no matter how many times I adjusted the vertical alignment on the rails it just seemed to be 'out' on the next time I operated the layout. Then I found the culprate - MDF IS EVIL! I had made the track base for each level of the fiddleyard out of 6mm MDF, supported under the whole length by 3/4" aluminium channel. However the MDF was only fastened to the channel about 3 inches from either end by 2 bolts. Seemed perfectly adequate at the time. However the application of PVA glue and 5mm foam to one side of the MDF meant that the final 3 inches were beginning to curve upwards so the rail level on the ends of the shelves was constantly change with respect to the entry/exit tracks.
     
    Once I noticed this was the root cause of the problem it was relatively easy to solve. I've now stuck a strip of wood under the ends of each level which means that the shelf can no longer lift and is held firmly in a vertical direction. Miraculously the levels then went back to how I'd lined them up originally and trains stopped falling off!
     

     
    The other issue was that the moving bit of the yard had got progressively heavier as I'd built more levels and loaded it with stock to the point where I needed to adjust the counter-balance to make moving it easier again. While buying another MDF board from Homebase, (taking the thickness of the counter-balance from 15mm to 21mm) I also purchased a sheet of 2mm clear styrene sheet. I've now cut this to the right size for the front and it make the whole thing look rather good. I intend it to be held on either by hooks or velcro so that I can easily take it off to deal with any derailments but the main purpose is to get the stock better protected from the dust that is inevitably associated with a spare bedroom.
     

     
    So at the end of the weekend I'm running trains around, I've got the track cleaned, sorted out a couple of errant wagons' back-to-back and reversed trains in and out of the good loop with out things falling off! I've also fixed a couple of wiring faults and finally connected the servo under my banner repeater signal to the lever on the frame.
     
    Mojo returned!
     
    David
  10. Fen End Pit
    The weekend gave me the opportunity to remake the ends of the bridge corner boards which I had to shorten to make space for the extra 10cm of fiddle yard. A short length at the end of the baseboard is built up with MDF and ply to a height which allows for a solid length of copper-clad PCB to go underneath the rails. This gives something solid to solder the rail onto and hopefully keeps everything from moving. I had to put an additional bit of bracing onto one of the main baseboards to stop it from moving (a good idea from my eldest Son was to re-use the original timber brackets which previously supported the old fiddleyard.
     
    The first length of MDF deck got bolted into the aluminium frame and then the first fiddleyard tracks soldered down to align with the bridge-board across the door. With a little bit of fiddling it runs ok. There is probably a slightly larger gap in the rails than I'd and I may go back at adjust that a bit. However the important thing is that I can push and pull stock into the fiddleyard without it derailing. I can also move the fiddleyard up and down and still run stock in and out without it derailing after returning to the same level.
     
    I've now started work on the other end so hopefully it won't be too long before I can at least run some trains around again!
     

     

     
    According to the counter this is my 100th blog entry, Hope some people are still finding this interesting, I find it good to look back and see what I've done previously
     
    David
  11. Fen End Pit
    Set up on Friday went smoothly, despite missing the right turning from the North Circular for Ally Pally. My Son did an excellent job at map reading (no new fangled Sat Nav for us!). The unloading was greatly eased through a helpful trader who had just finished using his rather excellent 4 wheel trolley which he kindly let us borrow, reducing the number of trips between vehicle and site considerably!
     

     
    Everything worked well on set up and we celebrated by visiting IKEA for Swedish meatballs before retiring to the hotel.
     
    With no repeat of the problems finding our way this morning we had a bit of an opportunity to wander before the show opened. There is a heck of a lot to see and it was great to put names to faces and chat to everyone. Thanks to 2BIL for his assistance, he is now a passed drag-line driver and as ever to Rad for his help.
     
    The show was busy, but not so full you couldn't see things and the space between the layouts is good. This afternoon the West Hall opened its vents in the roof and we had a really pleasant afternoon.
     

     
    Hope to see folks tomorrow, come and say 'hello'
     
    David
  12. Fen End Pit
    Well a couple of days off and a weekend's worth of construction and the frame of the vertical fiddleyard is now mounted on the wall. First up went the rack-mount server runners and then I hit the first problem, trying to fasten things accurately to masonary is a complete pain! Despite measuring accurately it is just impossible to actually drill a hole and get a rawl plug into exactly the right place particularly when you are trying to fix something to the resulting holes and have no margin for error. Once the runners were up of course the holes in the main moving framework wouldn't quite line up. I ended up having to enlarge the holes in the back of the square tube out to give about 1mm of adjustment so that the bolts would fit the bolt holes in the runners. Still up it went and it didn't fall off the wall overnight.
     
    Saturday and the framework to support the bridge boards and the counter balance was fabricated and put up on the wall. I've had to cut away a section of the square tube on the sides which is where the bolt mechanism is going to fit. As the main moving section has to be proud of the wall to make space for the counter balance the sections of tube on the sides are 12.5mm further forward than the support frame which is fastened on the wall. I intend to try and make the bolt mechanism driven by some meety servos so I can unlock and lock the yard with a switch (or ultimately an electronic controller that also drives a stepping motor to raise or lower the yard, don't hold your breath for this though!)
     
    Sunday was the difficult bit, taking the existing bridge boards and accurately cutting them shorter to fit the fact that the moving section is now 10cm longer than before. This involved trying to measure exactly how much length had to be removed when you couldn't fit the board in place and trying to saw 15mm MDF without damaging the C&L P4 track which was stuck to the top. Amazingly I was able to do this without causing too much damage. The result is that the yard framework now goes up and down and aligns with the bridge boards.
     

     
    From the door of the spare room the fiddleyard in the second from bottom track road.
     

     
    From the corner of the room the fiddleyard in the top most track.
     
    Next step then is to make 6 lengths of board 110cm x 10cm to form the base for each track level, I intend to lay the track on the lowest level and then align each of the ends of the track on the bridge boards to suit. Once happy with that I'll then work my way up the yard. That's the theory, watch this space!
     
    David
  13. Fen End Pit
    The re-construction of the fiddleyard started in earnest with a couple of days off. The original Mk-1 version was based on a lump of MDF as a back with some shelves of 6mm MDF fastened on the front. The unit had been built up one at shelf at a time at it had proved difficult to make each shelf align properly with the exit roads, basically as layers were added the previously alignment would get pushed out with the extra weight. I also had the problem that in retrospect I had mounted the rack-mount server tracks used as runners the wrong way up. This meant that as the unit was lifted up it tended to bow slightly away from the wall. The problem wasn't too bad but it meant that the front of the fiddleyard needed to be lifted slightly to allow you to push the connect bolts in and four bolts were needed two at the rear of the shelf and two at the front to keep the alignment in place.
     

     
    I was also limited to 1m long which was just a bit too short for the trains I want to run round Empire Basin.
     
    I purchased a load of aluminium L section and some 25mm box section Easi-Rec tube and joints from 'Aluminium Warehouse'. The delivery of 2.5metre lengths of metal certainly left my reception in no doubt that I was building something BIG! I also purchased a hacksaw blade for the mitre saw which made cutting the stuff up pretty easy. The intention is that if I measure and drill everything in one go I have a chance (hopefully) of getting it all square and staying square more than I did with the MDF. The overall length has been increased to 1.1m to allow for a Claud and 3 Mk-1 coaches. I different pair of runners were obtained and mounted so that they are 'extended' when the yard is in the lower position. This means that when lifted the yard won't bow away from the wall.
     

     
    This photo shows the moving bit of the yard supported in position on the original wooden supports for the bridge pieces over the door and spare bed. The shelves will be filled with MDF supported for the whole length on the aluminium angle. Since this picture I've added a couple of diagonal braces to hold the whole thing square and got it mounted on the runners. Tomorrow with luck I'll get the support structure for the counter-balance and bridge boards built.
     
    David
  14. Fen End Pit
    Now this locomotive has been very long in the making. Originally constructed from an Alan Gibson kit while I was at university 25 years ago this has always been a bit of a 'problem child'. The 2-4-2 wheel arrangement makes it virtually impossible to get around any kind of curve without resorting to some way of getting the leading and trailing axles to turn into the curve. Obviously the prototypical way of dealing with this would have been radial axle boxes but these are fiendishly difficult to make without resorting to a lathe and some serious engineering. This version of the chassis isn't exactly pretty, will probably horrify the hard-core springy beam fans and leave me open to intense critism from the purists. However it works!
     

     
    The two carrying axles run in bearings connected via a strip of brass pivotted from the centre line of the locomotive. The chassis is beam compensated with a single beam between th front and front-driving axle and two beams between the rear-driving and rear axle. I had a bit of fun getting the pivot points right to get the correct distribution of weight between the driving and carrying axles. Too little on the carrying wheels and they won't turn, too much and the locomotive looses traction and slips with anykind of load.
     

     
    I need to sort out another inside for the cab on this one, just like the N7 rebuild of a few weeks back. Also I need to get some pipework back on the front buffer beam and even out the weathering.
     
    Last up for the current loco builds another picture of the D16/3 which is now finished with the exception of getting a smokebox number. The cab windows got glazed after a fair bit of fiddling.
     

     
    Our little group met round at mine last week and we ran a few trains round and round. This was fun but really showed the limitations of the existing fiddleyard. Plans have been drawn up and an order went out earlier on in the week for a fair bit of aluminium section, I've decided to put aside thoughts of a radical re-design (linear paternoster, cassette moving robot etc) and go for what I hope to be is a better engineered version of what I had built already. I also hoping to make it about 10cm longer so I can accomadate slightly longer trains. Going from 100cm to 110cm will make quite a bit of difference. At the moment I can only run 3 mark-1s with a 'short' loco like the N7. Adding the exact 10cm means I can use the Claud. Also the typical freight will go up to loco+10+brake which looks much better than the current 8 wagons. I should be able to get 6 'levels' on the fiddle yard which will allow for a through road to be kept clear while storing 2 x Express Passenger, 2 x local Passenger, 2 x parcels, 2 x general freight, 2 x coal. The current plan is that the top 'deck' features a crossover so I can get stock from the up to down line off-scene for example to reverse a DMU. I'm also wondering about making a loco length cassette on the top deck so you can swap a loco without having to handle it.
     

     
    The original version never got the complete 6 decks, while it essentially worked ok it was never going to be possible to automate because the alignment bolts always needs a bit too much force to ldeal with the twist and slope in the various levels. This was cause mainly by building the levels one at a time. I'm hoping if I make the whole thing accurately, using Easi-rec aluminium tube as the main structure, it should make alignment more reliable.
     
    Watch this space!
     
    David
  15. Fen End Pit
    The original Wills kit was designed to fit around a Hornby Jinty or such like with a massive X04 motor protruding into the cab. Having built the chassis with something a little less 'old school' it was pretty clear that the absence of a floor, or backhead or crew was going to be a bit noticable. It isn't as if you can see much in the cab through the windows, it is just that you can really seen the absence of anything through the windows, if that even vaguely makes sense.
     
    So I decided to put together a representation of a backhead and give a crew something to stand on. The result is absolutely not intended to be an exact replica of an N7 cab, but at least it gives the impression that there was something inside the cab and that is a definate improvement.
     

     
    Not that you can see that much when the roof goes on!
     

     
    Still when it is sitting in the siding waiting to take the next trainload of commuters back to Liverpool St you get an impression of a cab and crew.
     

     
    The loco still needs some weathering as it is a bit of an even all-over black that needs some more work. Quite apart from the the dodgiest bits of the joins in the lining need to be hidden by dirty!
     
    David
  16. Fen End Pit

    Fitting TOUs

    By Fen End Pit,

    I spent a few hours today fitting the TOUs and servos which I built yesterday. I'm hoping a step by step guide might be useful to some people.
     
    The first step is to drill the holes which the TOU will go through to connect to the switch blades. If you are sensible and have planned ahead you will of course have drilled these before you stuck the point down or at least before you fitted the rails! However all is not lost as you can carefully drill a couple of pilot holes in the right place about 5mm from the end of the switch blade. Having drilled these I then VERYCAREFULLY opened the holes out to 8mm in several stages, making sure that the drill bit didn't go to far and touch the rails! A decent electric drill helped here (good to know I got something useful for working with my current employer for 5 years!). Designing the bracing on the board so it won't foul the TOU is obviously a must (spot the deliberate mistake).
     

     
    The TOU and servo mount were positioned under the board, It is a bit tricky to see both sides of the board at once and I found that putting some double sided tape on the units helped me stick them to the board while then allowing me to adjust a bit. It provides enough hold to them allow me to get a pilot hole drilled prior to putting the screws in.
     

     
    Then the length of .8mm brass wire can be bent up. I usually go for a short right angle bend and then bend that slightly to one side so that the short section will sit into the web of the bull-head rail. The wire can then be threaded down through the brass tube and soldered to the rail. Once both sides are done the TOU should move the blades smoothly. There is space for a little bit of tweaking if the blades aren't quite the right distance apart, the tube will take a little bend if you need 1/2mm of extra or less movement.
     

     
    Next job is to link the TOU to the servo, and this is where the real advantage of the servo comes into play. Because you can adjust the throw so easily you don't have to fiddle about making the linkage exactly the right length. I simply made a short length of steel wire by eye the distance from the hole in the TOU operating arm to the centre of the servo drive. Then I fitted one of the smallest servo arms (the servos have a variety of shapes and sizes supplied) and threaded the wire linkage between the two units.
     

     
    The downside of servos of course is that they need some electronics to make them work, but the 4 servo unit produced by the MERG (called a Servo4) is very easy to build and cheap at GBP 5.50. This unit has 4 double-pole-double-throw switches connected to it, one pole switching the frog polarity and the other switching the input on the Servo4. To set the board up you can either build and use the purpose built programmer which the MERG sell (probably a good idea to get one to take to exhibitions if you need to do any adjustment) or use a serial cable to a PC running the ServoSet application.
     

     
    The Servoset application runs on windows (there is a java based version available I believe for linux users). The left hand side of the display shows which servo you are programming and where it is connected on the Servo4 board. In the centre are the sliders which you move up and down to set the on and off positions and the speed you want the servo to move at. Once happy you just write the data to the board and you can disconnect the PC.
     

     
    The servos make a noise if you push them too hard so it is easy to get a feel for where to set the end points, you shouldn't need so much torque that the servo buzzes. The servo controller switches off the power to the servo after 5 seconds so that they are completely silent once changed (unlike some of the alternatives which stall a motor and can hum gentle to themselves).
     
    If you are offended by a brief plug for the MERG please stop reading now!
     
    Just to finish, a few thoughts about cost. A quick internet trawl shows a typical Tortoise point motor at about GBP 14.50, a Cobalt point motor at GBP 17.50 and a typical Servo at under GBP 3 and the MERG's Servo4 board at GBP 5.50. So, four points driven by Tortoises would cost GBP 58.00 while four driven by servos comes out at GBP 17.50. I think the difference pays for the MERG membership fee several times over.
     
    David
  17. Fen End Pit
    An evening with Scalescene's paper and card on Friday has resulted in the road bridge being basically complete. A mistake on my part mean that I had to do quite a bit of re-work as I'd not left quite enough room for the bridge to fit against the viaduct wall. Not quite sure how I screwed that up but there you go. The gab between the buttress and the wall which is very noticeable in the photograph will close up when I get the bits stuck in their final positions.
     
    To the right of the road going under the bridge there is going to be a wall with an entrance way into the low level coal yard. To the left will be the ground level buildings for the station.
     
    As you'll all notice the Claud is still missing its smokebox door number but is still heading up a parcels train!
     

     

     
    David
  18. Fen End Pit
    A bit of tidying up of the wiring today and I managed to get to a point where I could think about turning to the scenery on the next section of viaduct. This consists of a road bridge under the railway which will also have the station building at street level. The road itself will be wider that the arches of the main viaduct section so I have drawn out an elliptical arch which matches the height of the other arches but gives the right distance between the piers.
     

     
    Given this is a bridge over a public road I'm thinking that the company might have splashed out a little bit more of the bridge. Referring the survey of GER buildings I can see that in Chelmsford they went to the expense of using stone for the arch voussoir (remember that one for scrabble) and tops of the abutment.
     
    The arch itself is 132mm wide (33 ft). Does this sound about right? I found references to the standard being 12 ft per lane so I thought allowing for a couple of pavements this might be ok.
     
    Height at the road edge will be ~60mm (15') and 70mm (17'6") in the middle. The highway code website seems to imply that I'd need some 'low bridge' signage on anything under (16'6") so I may need so warnings for 'oncoming vehicles in middle of road'. I can find the current signage easily enough but what, if anything, was used in the 1950-60s?
     
     
    David
  19. Fen End Pit
    The banner signal has now been positioned on the layout. It is tight against the wall of the viaduct and I actually have to do a little bit of work as the wall of the parapet would actually be a bit too close. The driver's eye view shows the On and Off position. The Off is not quite a steep enough angle but I'm afraid it will have to do as getting a stepper angle would mean having to adjust the rather delicate push rod.
     

     
     
    The curve probably demonstrates why the repeater was necessary, particularly as the platform, canopy and back wall of the station will block any view of the starter from this point.
     
    The banner is controlled using a servo and MERG Servo 4 board. The servo is held on a simple plasticard holder which bolts through the baseboard. I had to make an extension cable for the servo to reach the servo4 board of about 1/2 metre but this hasn't impacted the performance of the servo. I think this shot demonstrates just how good a servo is for this kind of job. The ability to install it, and then adjust the throw of the servo from my PC makes setting up much easier. Apologies for the loose end of the signal wires, I need to extend them and the point rodding further along the layout.
     

     
    Looking at the scene overall the Metcalf water tower was built by my son a few years back. It will be replaced by a GER structure in roughly the same position so that I can have a water crane at the platform end. If anyone has any suitable prototype photographs around I'd love to see them.
     
    I think next up is going to be the last visible signal on the scene, the down home. This is probably going to be a bracket signal, the idea that the bracket positions the signal over the track so that it is more clearly visible on the inside of the curve.
     
    David
  20. Fen End Pit
    Do you refer to the colour of a signal as a livery? I suppose in these days we should consider ourselves lucky that they don't get repainted with each change of franchise. Fancy a signal in 'Barbie Rail' pink and purple?
     
    Anyway, following advice from folks here and more photographs from 'Adrian the Rock'
    http://www.roscalen....ratfordUponAvon I decided to repaint the post white, ladders black and also take the actual banner head a darker grey.
     

     
    I think the result looks a bit more suitable for my 1960's timescale.
     
    David
  21. Fen End Pit
    The internet is a great tool for research for this hobby of ours. Following inquiries on the Scalefour forum I was pointed at some drawings of banner repeater signals. I found few pictures on 'Adrian the Rocks' signalling web page http://www.roscalen....gnals/index.htm and following a quick email Adrian sent me a couple of pictures showing the rear of the banner signal without having to resort to Eileen's extreme products.
     

     
    At just under 11mm in diameter the result isn't big and has caused a fair bit of 'entertainment' in the burnt finger department. The head will be mounted on top of a suitable post and will probably have ladders up both the front and the rear as per the photographs.
     
    The fingers will heal up soon!
     
    David
     

  22. Fen End Pit
    Much burning of fingers later and the repeater head is mounted on a pole. The photographs showed ladders up the front, presumably for cleaning the glass, and the rear, for access to the bulb. The signal will be operated by a servo so the operating wire terminates in a little sprung plunger which is a bit of 3/4 inch long tube beneath the base.
     

     
    I've got to admit I'm quite pleased with the result and it will be nice to have a feature 'on scene' to demonstrate the aspect of the 'off scene' starter signal.
     
    Thanks to everyone who pointed me at different resources for drawing, photos etc.
     
    One last question.... Is the colour right? The photos I have are all modern and show the repeater, post and ladders all in grey like a modern colour light signal. However was this always the case? In earlier times (say 1960's) would the ladders have been black as they were on traditional semaphores?
     
    David
  23. Fen End Pit
    One of the joys of this hobby is when you realize that you have done something which with hindsight was probably wrong! I had originally planned to make the fronts of the viaduct part of a jigsaw board which would contain the lower level yard. However this would have made if difficult to deal with the bridge section and was also causing problems with the way in which the baseboard sections of the main line were going together.
     
    The viaduct sections were also not quite a multiple of the length between the sections of baseboard so I've needed to add an extra section of buttress in to give the extra couple of centimeters. Finally I've been able to fit a curved section of ply into the inside of the bridge and cover it with brick paper to suit.
     
    I'm quite pleased that I've actually motivated myself back onto scenery after building the Claud.
     
    David
     

     

  24. Fen End Pit
    Yesterday I visited ExpoNG and came away with quite a lot of inspiration and enthusiasm. I bought a motor to go into my P4 Barclay fireless.
     
    I particularly liked some of the 'single baseboard' layouts like 'The Loop' and drew up a plan to give an opportunity to run some of my 7mm stock which doesn't get a trip out anymore since I sold 'The Works'. This is based on a fictitious exchange between the Wissington Railway and a narrow gauge agricultural line. I'm imagining a river along the back with a bank along the backscene, on the left is a small pump house draining the surrounding fields, on the right a corrugated iron transhipment sheet. A few willow trees on the left to hide the 'duck shoot'. Total size is 80cm x 50cm
     
    The weird contraption on the right is a turn plate which allows the various routes to be switched easily. On the bank I could have a Dragline (what else) doing banking work and some portable track up zig-zagging up the bank with some skips of clay.
     

     
    Small pump house
     

     
    transhipment shed
     

     
    So, what do you think? should I walk away now!
     
    David
  25. Fen End Pit
    A bit more progress over the last couple of evenings. I've added some coal into the tender (I've got to clean off a bit of dilute PVA that leaked down the tender foot steps). I've also made up a couple of brass splashers that fit just behind the pony trunk wheels. At the moment there are just attached to the chassis with some bits of sticky-fixer just to see if the loco would still go around the corners!
     
    Also I fitted some Alex Jackson couplings to the tender so I can now enjoy the sight of the loco pulling something!
     

     
    Still needs a :-
    little more detailed weathering, probably just some dry brushing
    glazing (I think both windows were glazed)
    pipework on buffer beams
    smokebox number plate and shed plate (I know it is probably wrong but I think I'll have to put 31a on it even if this number was never actually allocated to Cambridge (it would have been if the Empire Basin loop had been built!)
    was there a loco power classification under the number and if so what, 2P?
    I think I also need a couple of oval builder plates on the front splashers
    I could do with a drawing or picture which shows the injector which I think was behind the footsteps on the right hand side under the cab

    nearly there then....
     
     
    David
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