david.hill64

I built 3 of these recently - not the easiest of kits to put together, but with care makes a nice looking model. Halfwit posted a step by step guide that I found very useful. It's in the archives I think.

You will probably find that a deal of cutting back is required underneath to provide adequate clearance for the wheels.

Good luck! I will watch with interest.

I had some great trips from Gloucester. These included Aberystwyth with class 40 haulage from Wolverhampton: I can still remember the turbocharger whistle as power was shut off on cresting Talerddig summit. Also our class 47 failing at Dover Marine and having to wait for a pair of 33's to be sent from Ashford. The driver thrashed them on the way back to Kensington Olympia where a Western was waiting to get us home. Happy Days!

Hi David,

 

The rivet detail is half etched for you with small dimples on the under side of both the footplate and splasher tops. After cutting out from the etch, and cleaning up the edges, the next job is to punch them out with a rivet press.

Mine is the Metalsmith version where the punch and anvil can be changed, to suit the size of rivet you want, and the depth of the rivet set with an adjustable stop.

The etched dimples are usually to big for the point of the punch and, to ensure you get a straight line, you can either have the point of the punch hard up against the same side of the dimple each time or, use the adjustable fence on the Riveter to keep the line straight.

Thanks Sandy!

If I am deemed to have been a good boy this year, I believe that Santa will bring me the GW models version. I am using the LRM gravity rivetter, which isn't bad, but the presses seem to give a much sharper, better defined shape.

David

Love the rivet detail on the running plate and splashers. Were they pre-etched or formed?

I usually use 'Plastic Padding' though the tube I have now is about 15 years old and doesn't set as well as it used to! The car body fillers are cheap and do the job well, being easily sanded down to a smooth surface. I haven't found a DIY car repair shop in Bangkok so recently I have been using Tamiya epoxy putty and this has worked well.

"No. 3" is E Borrows no. 37 of 1898, an 0-4-0WT formerly of Wallsend Slipway.  It is now in store at Marley Hill on the Tanfield Railway.  You did well to see it in steam!

Having fired and driven a Borrows well tank - Windle - when it was at the Middleton, I can only say that anyone who has ever seen a Borrows engine in steam has been very lucky! If I was booked fireman when this engine was rostered, I knew I had a tough day ahead. Happy Days!

I find for the minimal outlay the proprietary preparation is most efficacious!

 

Is it called Lillian and pink in colour?

A Crab might do it, or a Maunsell Mogul. Can't think of anything else that runs on a 5'6" wheel.

Stanier Mogul as well I think.

Welcome!

Looks like you are off to a cracking start!

Please keep the pictures coming.

Hi David,i was thinking of the 8" version.

 

http://www.ebay.co.uk/itm/The-Small-Shop-Photo-Etch-Bending-8in-Mk-R-Hold-and-Fold-SMS005-/111379560798?pt=UK_ToysGames_ModelKits_ModelKits_JN&hash=item19eebd395e

 

0 gauge is a whole new ball game to me,most of my tools are aimed at large scale model engineering,big `ammers & things

 

 

    Cheers,Ray.

Yes looks good. Not essential but useful.

I understand your comment about big 'ammers and things. A long time ago I was involved in 12" to the foot scale stuff, where most jobs could be completed with a set of stilsons, a 6' pipe and a lump hammer!

I got by for years without a Hold and Fold, but now I have one, I wonder how I managed without. I have the 5.5" which has been OK for everything to date, but bigger may be better.

I have a 100W one for larger work.

Will a 60W iron be large enough for the larger white-metal castings?

Jeff,

I would have thought a 100W iron would have been a recipe for molten castings (unless it's temperature controlled)!

I find a 100W iron useful on the thick DJH frames. Before I had that I had to resort to a gas torch (smokers' accessory I think) to get enough heat into the brass.

Hi David,the MOK Cl.4 looks a really good model especially as it`s nickel silver.Can i get the wheels & motor from Slaters?.Please excuse all the questions,7mm scale is a whole new ball game for me.Looking at your pic of the rivet embossing tool,i have a fully complete model engineers workshop so should be able to make one although the MOK kit appears to have them embossed already.

 

 

  Cheers,Ray.

Ray: yes you can get the wheels and motor from Slaters. I don't have my reference book with me so I'm sorry I cannot tell you which ones.

I'll add my name to those interested in buying the head frame etch.

Hi Richard,no,not particulaly,i am looking for a kit to build,2-6-4 or 2-6-2 LMS or LNER or a standard tank.,DJH V3 for example.I looked at DJH because i could get the wheels & motor etc.in the same package.

 

Another question if i may,i take it that the riveting on the tank sides is not done already,do they have etched dimples to guide me using,say,an automatic centre punch?.my experience of rivet detail is drilling a hole,dropping in a copper or iron rivet & using a hammer & rivet snap in 5" live steam!!!!.

 

Cheers,Ray.

For embossing the rivet detail there are several tools available: one of the cheapest is the London Road Models gravity tool, also available from Eileen's Emporium (no connection). There is a picture of mine in post 41 here:

http://www.rmweb.co.uk/community/index.php?/topic/91334-7mm-a4-merlin-from-a-martin-finney-kit/page-2

Look also at this thread:

http://www.rmweb.co.uk/community/index.php?/topic/92073-of-rivets-and-rivetters/

A friend of mine built the DJH Fairburn and had problems with the valve gear stemming from the motion bracket issue identified by Richard. The DJH/Piercy V3 will be a better choice (though I haven't built one) and the MOK Standard 2-6-4T is a wonderful model IMHO.

Brilliant! Please keep them coming.

For some reason I had always thought that the inlet for the air was in the sides of the loco and the exhaust air through the roof (hot air rising and all that).

 

Think of a class 40 after a hard run in the rain radiator fan running hard sucking a load of rain in and forcing it out of the sides and then running into a platform!!!!!

 

Just my thoughts

 

OzzyO. 

On a couple of test runs I had to pass through the engine compartment of an HST power car: the noise next to the engine was incredible, but the most uncomfortable bit was passing the cooler group. The air intake from the sides was so strong as to make you believe you were going to be drawn into the radiator bank!

This discussion inspired me to get the calculator out and do some approximate calculations.

Braking effort is provided by the combination of trains brakes and aerodynamic resistance (drag). To a first approximation we can ignore drag if we also ignore the effects of rotational inertia of the wheelsets and associated gearboxes and traction motors where provided.

The notional braking rate of 9%g for 125mph is actually an average rate from brake initiation to the train coming to stand. During the brake build up time the brake force builds up so that it then reaches the instantaneous rate which is about 9.6%g. However, to get a feeling for the problem we can ignore the effect of the free run time and use the average rate. I will also for simplicity assume that g is 10m/s/s so that 9%g = 0.9m/s/s

The key distance to achieve from 125mph is to stop in 1740m. This is the distance from the W125 brake curve. It allows a margin of 300m for variation in friction material performance and adhesion for a standard signalling distance from double yellow to red of 2 * 1020 = 2040m

Assuming linear deceleration, basic physics tells us that braking distance is ((initial speed squared) minus (final speed squared)) divided by 2 divided by deceleration rate.

So the key speed figures are 125mph = 55.8m/s and 90mph = 40.2m/s

Assume that an HST power car has a mass of 70tonnes and a trailer car a mass of 30tonnes.

In the post 1985(ish) set up with single stage brakes on the power cars set at 9%g retardation, the braking distance of any combination of power cars and trailer cars from 125ph is simply (55.8 * 55.8) / (2 * 0.9) = 1730m.

For the original set up with two stage brakes we need to consider the distance traveled from 125mph to 90mph and then the distance traveled from 90mph to rest.

For a 2+8 consist, the brake force from 125 to 90 is the sum of the brake force of the trailers plus the brake force of the power cars. Trailer brake force is proportional to 8 * 30 * 9. Power car brake force is proportional to 2 * 70 * 6. Total brake force is therefore 3000 units and deceleration will be 3000/train mass = 3000/380 = 7.9%g. 

From 90 to 0 using the same methodology gives the deceleration rate of 10.1%g,

The braking distance from 125 to 90 is then 947m and from 90 to rest is 800m or a total braking distance of 1747m. Given the assumptions in this simplified calculation that is close enough to 1740m not to matter.

Similar calculations give the stopping distance of a 2 + 7 set as 1752m; 2 + 5 as 1765m and 2 +4 as 1775m. A pair of power cars on their own would have been about 1920m.

When you are so close to the 1740m limit then you need to do the more detailed calculations. In particular the assumption that rotational inertia can be ignored is not valid for short formations including 2 power cars as the motors, gearboxes and wheels provide significant energy that has to be dissipated by the brakes. This extra energy contributes to brake fade where the friction coefficient between the pad and disc decreases with temperature. This will be worse on the power cars in short formations at high speed. I have also ignored the fact that in short formations the power car cast iron tread brakes will be less effective as they will run hotter: once the interface starts to melt friction falls considerably.

The Train Performance team's computer had all of these variables included and I can readily appreciate that as originally equipped a 2 + 5 set may have been just inside the curve while a 2 + 4 just outside.

I think the Top of the Pops run was in 1984 before the brakes were changed.

With the original two stage braking then brake performance at higher speeds would definitely be impacted by short formations. As I said in my post the braking effort on the power cars was reduced significantly above 90mph (to about 6%g if memory serves correctly) and upped to about 12%g below 90.

 I know from being involved in the tests with two power cars running on their own with the new brakes that brake performance fully met the W125 curve at all speeds. Subsequently we did tests on a full rake when the new pad materials were introduced to the trailers and confirmed the results. The braking distances for a full set were not materially different than those running a pair of power cars on their own. Admittedly this is nearly 30 years ago and it is possible - though unlikely - that there might have been a reduction in power car braking performance since then

Most Mark 2's were cast iron block braked and would have been a liability in a set running at high speed. Don't forget that the standard braking rate for loco hauled vehicles at that time was only 7%g and the 9% rate was applied only to HST vehicles (and later IC225 sets) that were required to stop from 125mph in signal spacings that were designed for 100mph running. The ex Glasgow-Edinburgh push pull vehicles that were used by BR Research had modified distributors allowing the brake rates to be adjusted according to need. Any test results that were obtained with mark 2s are irrelevant when considering HST power car and trailer car performance.

There was an interesting problem first noticed on the western when the HST's were introduced. SIgnal spacings are reduced on rising gradients to take account of the shorter stopping distances. As the percentage effect of gradient was smaller with higher braking rates (if a gradient gave you a 1%g effective additional braking rate then the total service braking rate would be 8%g for 100mph stock or a 14% increase. For 125mph stock braked at 9%g the benefit was only 11%) there were some uphill locations where HSTs were limited to 120mph where normal line speed was 100mph and the expected HST limit would have been 125mph.

As the project engineer involved in the HST tests- and subsequently head of braking at BR Research - I am sure my information is correct for that time period. As I said in my post, I do not know what the current situation is, but I think it unlikely that the braking effort will have been reduced on the power cars.

While the discussions about reduced speeds being applied for loco hauled coaching stock are correct, the same rules did not apply to HST's. I am not sure of the current position as I am no longer in a position to know.

HST power cars are not locomotives,which generally have lower brake force than coaching stock: therefore on a typical rake of loco plus coaches, much of the braking effort is provided by the coaches. When BR research ran test trains it was usually necessary for additional coaches to be added to the test rake to make up the brake force. Some disc braked mark 2 coaches that were previously used on the Glasgow-Edinburgh services were used for these purposes. I used to do the calculations to determine how many additional vehicles would be necessary.

HST power cars are different: they were designed to brake their own mass and not rely on the braking effort from the trailers, but with a slight complication. As originally built, the power cars had both tread brakes and disc brakes, with a notional 20% effort devoted to the tread brakes. I say notional as the friction coefficient of cast iron brake blocks increases considerably as speed reduces, so at low speeds the tread brakes were providing more brake effort. The complication comes that at speeds above 90mph the braking effort on the power cars was reduced so as to stop overheating of the brake discs and pads. At these speeds the trailer cars were providing more of the brake force Below 90mph the brake effort was increased on the power cars, which were then providing more brake effort than the trailer cars. So in the early days the braking distances of 7 car sets were different from those with 8 cars.

Even so the brake discs on the power cars continued to give problems so in the 1980's a change was made. The original design was a split disc which meant that if a disc needed to be replaced it could in theory be done without removing the wheel from the axle. The problem with split discs is that they need multiple attachments (bolts) to stop them flying off the wheel under the actions of the rotational forces. However, putting in lots of restraint to keep the discs on the wheel means that thermal expansion is constrained, so high forces are generated by the heat during braking: these high forces result in cracks which eventually if uncontrolled cause the disc to break up and get ejected. Initially this happened a lot with the trailer cars, so a different higher quality grade of cast iron was developed for use with the trailer cars. This was relatively successful. It was not so successful on the power cars so a trial was set up with brake discs of a continuous ring and a retaining mechanism that allowed the disc to expand and contract under the action of heat while still being retained on the wheel. At the same time the brake pad was changed to a conformable non-asbestos type and the two stage braking disabled. The brake force was set up so that the power cars braked their own weight over the full speed range. The tread brakes were still active so the actual total braking force is non-linear but still met the braking curve - the W125 curve - at all speeds.

When it came to braking trials, which were held on the western region - the WR operating department initially objected on the grounds that a pair of power cars were not allowed to run at 125mph on their own as they were locomotives and therefore subject to short train restrictions. The argument that they are not locos, but power cars that had design braking effort identical to coaches, won the day and tests were carried out using a pair of power cars running back to back at speeds of up to 125mph (and a bit!). The tests were successful and all of the fleet was modified. I was the responsible project engineer for the change and was on the tests and the acceleration was incredible!

In theory the braking effort of any combination of HST power cars with any number of trailer cars will be nominally identical with only differing train resistance and the usual variations in brake pad friction performance giving any difference in stopping distance from a given speed. So short train formations need not be speed restricted. But as I said above, I am no longer in a position to know what the current rules are. If restrictions are in force they are not there for any engineering reason.

I believe that Class 67s have disc brakes and therefore do not have the problems that cast-iron tread braked locos have.

Edit for comment on 7 and 8 car sets and 67 brake performance.

David

Precisely Sandy.  Austerity is rare beautiful, if ever.

 

Right, the tedious parts are now complete. I have the inside of the cab to do and buffers to assemble and fit.  Then I can think about priming it, at last.

 

The dome does not fit to well, it has a nose down attitude. So I filed as much as I dare from the rear and put small amount of packing under the front end. Tomorrow will see the filling and filing to blend it all in.

 

IMG_2379.jpg

 

IMG_2380.jpg

Thereby proving you can make a silk purse from a sow's ear..............

Well done Ken!

  I've been considering trying  some of the liquid glazing stuff (I forget what it's called) to hold the windows in place - it could be a better option - but I've not got around to trying it yet. 

 

I used canopy glue for the first time recently and wouldn't use anything else now. Really good stuff and fills in any small gaps between glazing and frame.

The Black Hawthorn is produced in kit form by High Level kits.

The Peckett will be a bit more difficult. Agenoria has plans for an 0-4-0 Peckett, but I think not the same type.

^^^

Thanks to mandatory high brightness headlights, I think yellow panels are redundant.

That argument was tried by Heathrow Express who wanted a derogation for their EMU's. The T&RS sub-committee didn't accept the arguments then. I cannot remember precisely the argument why it was refused, but I think it was on the lines of yellow is good, lights are better, yellow plus lights is best; there can be no justification for departing from best practice when the only reason is aesthetics and the cost of yellow paint is trivial.

It's all very well thinking that a German loco looks better, but when you consider that the staff fatality rate in Germany is several times that in the UK, you might think that there is some point in the yellow. (OK, I know it is probably more to do with methods of work, but anybody who proposes removing a safety measure from the railway needs to have a very good argument why).

Will also be watching this with interest. Rebuilds are more interesting than straight builds, imho.

Does that mean we can look forward to the 'Rebuilding Alcazar' thread?