John Brenchley

Thanks Andy and Don

Very useful diagram thanks Andy

I'm just completing the woodwork for the next baseboard for my model of Tavistock so want to lay a road surface as well as the track supports so need to get the vertical heights correct.

Best wishes

John

Can I ask any road or bridge engineers if they can tell me where the rail height is likely to be as it goes over the bridge in the below picture of the Pixon Lane bridge in Tavistock please.  Unfortunately, I haven't got any pictures at rail level. Track was lifted 40 years before this picture but it looks from the left as if it might have been roughly at the level of the stone course above the white line.

Also, can I confirm that the clearance of 12' 3'' is measured to the point below each of the vertical white lines, not the top of the arch.

Thanks

John

It might help take off if you incorporate a bit of a ramp.

Hi Kevin

Thats all looking really good.

A silly question perhaps - if you are 3D printing a carcass, could you not print the bricks on it as well rather than having to add a Plastruct layer over the top?

Best wishes

John

Thanks Ian and Duncan

I've looked at both web sites and the Narrow Planet (Lightrailwaystores) one looks to be ideal for ordering any number that one wants.

Best wishes

John

Hi Ian

A quick question regarding your small tank engines please.

I'm sure you have probably mentioned it somewhere in your writings but is there a 2mm source for the loco number plates?

Thanks

John

13 hours ago, Nigelcliffe said:

PWM controllers, using cheap PWM devices from ebay and the like, were discussed in an article in the 2mm Magazine in August 2020 written by James Batchelor .   Worth a read, as the article builds a very effective and cheap DC controller with a meter attached.  

 

 

The issue of "not going down to zero" is whether the PWM device output can get to a zero width pulse or not.  Some do, some do not.   
If it doesn't go all the way to zero, then the quick solution is two or four diodes added to the output to remove the bottom 0.7v (one pair of diodes) or 1.4v (two pairs of diodes) from the output.  It also drops the top-voltage by the same amount.  

 

 

- Nigel

Thanks Nigel for sending a reminder of that article 

A straightforward description and some simple wiring diagrams.

John

Given the low cost of these PWM units, I think the easiest plan is to order one and hook it up to the rear terminals of the H&M Executive, turn that controller up to full 12v power and see how the PWM unit works at slow speed control.  If happy, I can then buy a dedicated 12v supply, and build the PWM unit into a controller box with direction switch etc.

Thanks for everyone's help.

Best wishes

John

4 minutes ago, Donw said:

One of the things with these PWM units is just how slow can it go.  They work by adjusting the ratio of the pulses to the spaces.  They give good motor control but some will not go slow enough for our use. The only way you can tell is to try them as far as I know.

 

Don

Thanks Don

On that basis, my simple electronics brain says having a lower voltage DC supply would give a slower speed - though would this mean they just stall more often at the lowest speed?

John

On 05/06/2022 at 16:30, 2mmMark said:

 

You can ignore that paragraph if you use a 12vdc plug-in power supply of something like 500ma. This will be written on the power supply.

Here's a very simple schematic for you. 

http://davidksmith.com/modeling/projects/throttle.htm

The LED Dimmer can be replace by this or something very similar
https://www.ebay.co.uk/itm/275254025141


Mark

Thanks Mark and others for your suggestions.

If I go for the PWM route, would something like this also work - specifications seem the same as in your link above have the control knob separate is a bit more versatile for fitting in a control box.

https://www.ebay.com.au/itm/254692769428?chn=ps&_ul=AU&_trkparms=ispr%3D1&amdata=enc%3A1grW0IFPgQ8Sj5PKYSLIpag45&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&itemid=254692769428&targetid=&device=c&mktype=pla&googleloc=9070549&poi=&campaignid=15984321586&mkgroupid=&rlsatarget=&abcId=9300814&merchantid=263026884&gclid=EAIaIQobChMInuqnttSf-AIVT5NmAh1HJgbSEAQYCyABEgIVoPD_BwE

If my understanding is correct, I need a 12v DC power supply.  A local electronics shop has one like this - suitable?

https://www.altronics.com.au/p/m8932b-powertran-12v-dc-1a-fixed-2.1mm-tip-appliance-plugpack/

They also have versions at 12V but higher amps ie 2A, 3A, 4A - do I go for the lowest amps?  Is the fact that most of the PWM units are 2A or higher relevant?

They also have a  9V DC, 0.66A version - would this be better for slow speed control?

Thanks

John

Thanks very much Mark

I'll follow up all those links

Much appreciated

John

21 hours ago, 2mmMark said:

I'm quite keen on the inexpensive PWM speed controllers available from ebay & other sources. They work well with a variety of motors.  I'm using one on British Oak and it copes very well with my locos which have motors ranging from the traditional open frame Tenshodo to Tramfabriek coreless.

Here's how I built a controller:

It's important to find one with a 0 to 100% duty cycle. Some are not zero which in simple terms means that the power is not off completely so a loco with a very efficient motor can creep slightly with the control at its lowest point.

I have tried a Morley Vesta controller but I found it didn't give the very fine slow and steady running I was after.

Mark

 

Thanks Mark

I have just read your description on British Oak.

It sounded quite interesting till I got to this paragraph :-

For British Oak, I tapped into the 12vAC feed already provided for the plug-in controllers I use, like the Pentroller. The AC feed is taken to a small solid state bridge rectifier

(the black box at the bottom of the case) and from there, the rectified feed is fed in the controller, which has screw terminals to make the job easy. The output from the controller is taken into a DPDT reversing switch with a centre-off. This serves to isolate the controller when a plug-in unit is in operation. If this is not done, there is a strong possibility the two controllers will interact with each other.

For someone with no electronics knowledge, this caused heart palpitations and a cold sweat - tapping into 12vAC feeds, bridge rectifiers etc - help!

I could probably solder together a set of components if I had a shopping list and a wiring diagram but without, I haven't a clue.

Anyone have suggestions for a really good off the shelf unit?

thanks

John

DC Controllers

I'm looking to upgrade my current controller (an ancient H&M Executive) and would welcome some suggestions.

I have a mixture of motors including Maxon and the Association's more recent can motors.

One that I have found online is a Morley Vesta N Gauge Crawler Zero Two Controller.  Does anyone have experience of this?

Thanks for any suggestions - at this stage, I'm not proposing to move to DCC.

Best wishes

John

3 hours ago, dpgibbons said:

Exquisite!

Thanks very much

Best wishes

John

4 hours ago, brianusa said:

hi John, I took another look at your work around the weir at Tavvy and noticed even the start of the canal down to Morwellham Quay.  Spent many an hour traipsing around this area, the Incline and the docks be fore they were dredged and became a popular tourist attraction.

A pleasure to see it all again!

   Brian

Hi Brian

Thanks for your comment.

Your reference to the Tavistock Canal got me looking for more information as I didn't realise it started near the weir.

What I included in the model was just the salmon leap.

Looking at picture on Google, Is the start of the canal some sort of sluice that allows water to flow out of the Tavy just above the weir and salmon leap - if so, I omitted that bit due to ignorance.

Best wishes

John

Looking great Jerry

Not being a Midland modeller myself, you lost me with your reference to "comode handles" - could you explain please.

Thanks

Best wishes

John

Thanks Jim and  bécasse for adding your pictures again - much appreciated

John

Re-posting the photographs

I've just finished adding back all the photos that I had previously included in the past 7 pages of this thread.

To return the continuity of the thread to the way it was, I wonder if it would be possible for other modellers who had included pictures in their replies to upload them again. My thanks to Ian Morgan who has already done this.

I realise this is a bit of a nuisance to do but it would make re-reading some of the comments much more logical.

I've had a read through and I think the following people have added pictures - if its not too much trouble and you still have them available, I'd really appreciate it if you could "edit" your comment and re-attach your pictures.

Winchat - page 1

becasse - page 3

JohnBS - page 3

queensquare - page 4

JohnBS - page 4

Caley Jim - page 5

Thanks very much

Best wishes

John

D1661 LMS Cattle Wagon

Along with the Midland Railway cattle wagon shown in the previous post, I had also purchased an etched kit for the LMS cattle wagon built to D1661.

Although the method of building the kits is similar, the different style of top rails in the LMS wagon make this a kit for the masochists among us.  On the Midland wagon the rails pass through the uprights so can be represented by just two continuous wires each side.  However in the final style of Midland van which was perpetuated by the LMS in D 1661, the rails are fitted individually outside of the uprights as can be seen in the picture below, taken from the 2010 edition of Essery's book "An Illustrated History of LMS Wagons Volume One"

As with the Midland kit, each side is made up of 4 layers.  The bottom layer includes the horizontal and diagonal planking, the next two layers provide the outside wooden framing and the final layer has the various ironwork supports and brackets. 

The middle two layers have etched holes for the ends of the rails which I bent up from 9 thou steel guitar strings, each rail ending up looking rather like a staple.  Many attempts were rejected as not quite the right length but eventually I got 8 that fitted correctly for the first side.

The four layers are numbered 1 to 4 on the etch so it would seem logical to solder them together in that order which is what I did with the Midland wagon.  However I found that the quantity of metal tended to form a heat sink and it was tricky to get the tiny delicate pieces on the 4th layer to solder properly.  So for the LMS wagon I tried working in reverse order.  Having thoroughly tinned the back of the ironwork, I first soldered layer 4 to layer 3 and then added layer 2 to the back of these.  At this stage the "legs" of the 8 rails were pushed though the etched holes and then soldered in place from the back of layer 2 .  The surplus bits of wire were then filed back flush with the back of layer 2 and finally layer 1 was soldered in place.

One other slight change in construction I make is to remove most of the top and bottom of the etch surrounds and just keep the sides that have the locating holes.  This allows the soldering iron to be run along the top and bottom edges of the wagon making it easier to transfer heat to all the layers rather than waiting for it to pass through them all just from the top or bottom surface.

The finished cleaned up first side is pictured below.

That took about a week so it will be a while before I can post a picture of the finished wagon.

At least I'm only intending to add one of these to my wagon fleet - I certainly don't envy anyone wanting to make a rake of these wagons to replicate the picture below.

Though since the etch now seems to be currently out of stock, perhaps you'll be saved from such torture.

Best wishes

John

2 hours ago, Mikkel said:

That looks just right and completely believable, John. Apart from the trees at the front, the group at the back on the left hand side also looks very good I think.

 

The lettering on the horse-drawn coal wagon works well too. I hope Mr Bailey won't run into trouble with the unions, they are probably a bit baffled by his sudden conversion 

 

Thanks Mikkel

The vegetation on the embankment behind the left hand curve on the corner baseboard can be seen closer up in some of the pictures I posted of the layout taken from that end earlier on this saga (middle of page 1)

Best wishes

John

10 hours ago, Caley Jim said:

I agree with the others, John.  Despite having no knowledge of the area, my first impression was how natural it looked.  The dead and fallen trees are a nice touch which just adds to that.

 

Jim

2 hours ago, brianusa said:

Lovely work all round.  Many years ago, I was lucky enough to wander around the station area in its last years.  Sadly, didn't really appreciate it all then, so thanks to the quality modelling I can visualise it once more.

    Brian

Thank you both for your comments

Its good to hear from those who knew the station Brian.

I did spend some time in Tavistock when I visited the UK in 2009 but of course, nothing was left of the site by then.  I did take pictures of the river, St John's Lane plus the cottages and cemetary on Dolvin Rd with the railway embankment behind it which have been useful.

Best wishes

John

23 minutes ago, bécasse said:

I suspect that your ultimate rendition of the tree and other growth along the river bank is very close to how I would have ended up had I been doing it. It both looks natural and provides good viewing windows of the railway that lies behind it.

Thanks bécasse, much appreciated.

31 minutes ago, Siberian Snooper said:

The new trees and positioning are a lot closer to the prototype now, without being overbearing, great work!

 

 

Thanks very much

Its good to get confirmation from someone living nearby who's familiar with the location.