Some suggestions:
The West Wilts Model Railway Circle based at Steeple Ashton near Trowbridge, might have a local expert and be worth a try.
East Somerset models has a portacabin type shop in a shipping container at Cranmore station on the East Somerset steam Railway, used to be run by Ian Stoate who is/was an N gauge modeller. They have quite a lot of N gauge stock.
Titfield Thunderbolt Railway bookshop on the outskirts of Bath run by Simon Castens who was/is a gauge1 modeller.

I have no connection with any of the above other than Knowing some members of the WWMRC and being an occasional customer of ESM.

Present day Westbury is the marshalling point for stone trains from Merehead and Whately quarries to mainly London (I always jokingly say that they are moving the Mendip Hills to London in small chunks).

Martin

Martin, thanks for suggesting some resources. I'll definitely visit Titfield Thunderbolt Railway, and maybe Cranmore Station. I've also been told that the Frome Model Centre has an excellent inventory. West Wilts Model Railway Circle meets on Wednesday nights, so that is a bit problematic.

Leon

Leon

Hmm.  I have just been having a close look at wheel and track standards. I was concentrating on the differences between what I am doing and the European (NEM) standard: it turns out that what I have ended up with is pretty much identical to the American NMRA standards for track (S-3.2) and wheels (S-4.2).  The key dimensions are near enough what I am working to - 7.65mm back to back, 0.51mm flange width, 0.71mm flangeway, 0.76mm check rail. So possibly the solution here is just to work to NMRA standards.  Americans build their own code 40 track, so there should be track and wheel gauges available.

Richard

A useful Sunday's work, I think.  Having started this thread about wheel and track standards:

http://www.ngaugeforum.co.uk/SMFN/index.php?topic=41479.0



I had the idea of narrowing down the check rail clearances on Longfram to see what happened.  I have used this technique before to improve running on Peco code 55 frog crossings. I glued bits of 10 thou Microstrip along the inner edges of the checkrails, waited for them to harden and then trimmed and cleaned up to give a nice smooth check rail gap around 0.75mm.  They look a bit obtrusive so I will try the brown marker pen idea when I can get one.



I then eased out the back to backs to 7.6mm on a few vehicles and my BRCW type 2 and tried running trains. Straight away I had problems with the turnout closest to the level crossing, all the others were fine.  My turnouts are modified Finetrax with soldered rail crossings, the offending turnout was the first one I did and the gauge was down to 8.7mm in a couple of places.  I managed to rectify the worst of its problems although there is still a noticeable change in rail top levels just past the frog, you can stand a four wheeled wagon straddling the frog gap and it will rock on three wheels.  It's not as bad as it was though.

I also plugged in the computer to adjust the throw on one of the turnout operating servos which was not quite closing the point blades properly.  I have found that with the MERG 4 servo software, if you change the settings on one servo you have to redo the other three as well, otherwise when you save your new setting for the first servo it will wipe whatever you had programmed for the other three and replace it with a neutral default setting. Perhaps I am doing something wrong. I now decided I needed a second loco, regauged my J39 and found that the tender drive would not run smoothly through turnouts no matter how much I fiddled with the back to backs.

Out with the digital caliper again (that thing has had a lot of use this weekend).  It is quite difficult to measure the width of wheel flanges in N gauge but the tender wheel flanges were visibly thicker than anything else on the layout (including the driving wheel flanges on the loco), around 0.6mm as best I could measure them, when everything else I could lay my hands on came out around 0.45mm.  Combined with slight inaccuracies in the dimensions of my track at a few critical points, that was enough to prevent smooth running.

In the end I pulled apart the wheelsets and turned down the wheel backs using a minidrill and file to take around 0.15mm off each one. The wheels are plated brass and easily fettled in this way.  I put it all back together (having adjusted the pickups) and now had a loco which ran fine on plain track but slipped to a standstill going through the turnouts.  After more fiddling I found that by opening up the back to backs and shifting the wheel positions very fractionally relative to the drive gears I had managed to set the thing up so that the gear on the centre axle was dropping out of mesh with the spur gear between it and the rear axle,  On the J39 the motor drives the rear axle with the other two being geared to it. So I only had one driven axle, not three.  A brass shim washer on the centre axle restored normal operation, and the J39 now runs better than ever.

In fact, the whole layout runs better than ever.  A lot of the rough running through pointwork that I put down to a warped track base, actually turns out to be a combination of inconsistent back to backs and a couple of easily fixed rail alignment issues.  Narrowing the check rail clearances has forced me to deal with these problems, and I am now getting the smooth ride through turnouts that I should have had to start with, even though the crossing gaps are still a little wider than they would be on turnouts built to  0.75mm check and wing rail clearances from the start.

If this layout is ever going to see the inside of an exhibition hall I will need to lift and replace the turnout opposite to the signal box and the track leading to it (across the level crossing).  That bit is never going to be quite right as it is.  I think that should be do-able although fiddly as I don't want to demolish the surrounding scenery and buildings.  For now trains are still running: one of the newfangled diesels, possibly on a crew training turn, awaits departure for Morpeth with a pair of Mk1s still in the old "blood and custard" livery.



Richard

I have two CDU's - one with two caps and another with four.

For our use, the number of separate capacitors doesn't matter; it is the total combined capacitance ( the uF number)

The best analogy is 2 pint glasses holds the same amount as 4 half-pint glasses...

Kato model from TrainTrax : £84 plus low postage (less from June 1st with 10% discount offer).

MDS from MDS or elsewhere: €147.50 (~ £130) plus dearer postage.

No contest on price. Kato much cheaper.

I can see that the MDS model has a lot going for it, but with better windows, descent pantographs, and a better silver paint finish on the roof, I still maintain it could have been so much better.