Back to back problems on Hornby standard points.

[gazzarose]

Evening all,

I've been do more work on my boys layout for Xmas and now the track is all relaid I've been running various configurations of trains to check everything works but I've been having some problems with derailments on the points.

I originally had problems with the 'Annie & Clarabel' 4 wheel coaches, which are just the old 4 wheels coach Hornby have had for years. I then tried running a couple of the old Triang LNER Teak coaches that I bought used. They orginally had the plastic wheels with metal 'tyres'. But as I had a few plastic wheeled coaches and wagons from when I was a kid I had bought a few packs of new Hornby metal wheels. I swapped all the wheels to the new type and checked the back to back with my Markits 14.5mm back to back gauge and they were all too tight so I opened them up on one coach and tried running it through the points and it derails the majority of times. I then tried the coach with wheels straight from the packet that were less that 14.5 and they are perfectly reliable. I then remeber that I had used the back to back gauge on the Thomas coaches because they were tight, so it seems that if the back is set to the 'right' measurment it causes problems. I have tried running the 2 different width wheels between my fingers over the points and the correctly set 14.5mm wheels would catch on the plastic frog, but the slightly narrower ones are fine. I've only got a freebie plastic vernier gauge at home, but that says the back to back gauge is 14.5mm so that seems right, it just seems that the Hornby points don't like the 14.5mm back to backs. Should I readjust all the wheels to the ~14mm measurement which seems to be reliable, or do I have a go at filing the plastic bit that I think the wider wheels are catching.

I got the back to back gauge to check some of my older rolling stock as well as the new stuff after reading various reports of Hornbys inaccurate setting of back to backs but it seems that Hornbys tighter setting is on purpose.

Any help would be appreciated so I can get everything running reliably for Xmas morning.

Thanks

Gareth

[gazzarose]

I've been doing some googling and there are other people out there having the same problems when using the 14.5mm markits gauge. One forum topic also had a link to the 00 standards gauge and that says that the back to back should be 14.4mm. The difference of 0.1mm seems like nothing to people like me who are used to using a tape measure in work rather that a vernier but I guess wheel scaled down 0.1mm is huge. Brother on the other hand is a CNC machinist and to him 0.1mm is massive. Ideally I should turn the gauge down a bit, but I havn't got a lathe and my brother no longer works somewhere he can do me little hobbles so I down so setting the back to backs by trial and error or file a bit off the gauge and try and keep it as straight and flat as I can.

[brian1951]

Hornby points have never been the best, Peco are better, having said that back to back measurement of 14.4 should be ok, more important is the point being laid totally flat with no movement.

[Walkingthedog]

I use a 14.5 gauge and have no problems on points.

As Brian stated it is important that points are absolutely flat, a track pin as near to the centre should do the trick, and it is better if points are entered from a straight and not a curve.

[gazzarose]

I'll have a fiddle tomorrow and see if I can get them to run reliably. I think I'll just got with trial and error adjusting the wheels for now and not start filing the points and do something I can't undo.

I used Hornby track because I already had some from a couple of Thomas sets that I had bought. I had considered getting all Peco but it would have meant wasting some track that I already have.

If and when I do a fixed layout in the loft I'll be using Peco I think, mainly for the increased range of track options.

[Brian]

Peco Setrack prefix 'ST' and all Hornby current track are fully interchangeable and can also be connected together. They both use Code 100 rail and all points are Insulated frog and to the same size and radius. You can replace a Hornby point with a Peco Setrack one. When two points of the same hand are placed together to form a cross-over they automatically set the two parallel tracks to 67mm centres.

The difference comes in OO with Peco Streamline prefixed 'SL'. Which its sold in Code 100 rail as well as the finer Code 75 (there are other sizes of rail too, but mainly produced for the US market). Track and points have no rail joiners fitted - sold separately, and track is only sold in flexible one yard (914mm) long lengths.
Peco Streamline points are available in both Insulated frog (SL-nn) and Live frog (Electrofrog SL-Enn) and some are now beginning to become available in the Unifrog (SL-Unn) variant too. All of these points are not a direct drop in replacement for any Hornby or Peco Setrack point, as Streamline are to a much larger footprint and all are to a much greater turn out radius. Also when two of the same handed Streamline points are placed together to form a cross-over they automatically space the two parallel tracks to 50mm track centres.

According to the Double O Gauge Association UK wheels should be spaced with a B2B or 14.4mm +/-0.05mm Also the Front to Back F2B distance can be critical too. See http://www.doubleogauge.com/standards/c ... wheels.htm Older wheels on locos from before say 1999 may not be to RP25 profile and have wider wheel flanges, so their F2B distance may not be correctly set, which can cause running problems through more modern points.
That said, and as stated by others, if any point is not laid dead flat both along its length and across it throughout its length, then except poor running! As also stated, often a point can be slightly raised in the middle area leading to the frog from the switch blade direction. By drilling small hole in the middle of a sleeper near to the frog and fitting a track pin it will pull the centre of the point down flat and often resolve that problem.

[gazzarose]

I've been having a fiddle this morning and pinned the points down to make sure they were all nice and flat but it made no difference. Yoy could feel the wheels catching on the frog as it went through. I had a rummage through my wifes make up box and found a sandpaper nail file. I thought it was worth a go on one point as an experiment and after a little 'massaging' everything runs through there smoothly and with no jumping so I repeated the massaging on all the points and it all smooth as a babies bottom. I guess the Hornby molds aren't as accurate as they would like them to be.

Thanks for everything that replied.

[footplate1947]

It is not easy to give advice about Hornby wheels unless one knows which wheels we are talking about. For instance, are we talking old wagons bought second hand or are we talking about more up to date finer scale wheels as Hornby fit on the latest offerings. The old Hornby wheels used to be quite chunky to say the least. If it is the old plastic wheels then best advice would be to change them for a new finer scale set of metal wheels. As said before the Hornby points have never been the best choice in my opinion.. I say that because the last time I said that some did not agree. The I think the majority of modellers seem to prefer Peco. There are other makes which which have built in ballast and some look very nice and tidy but tend to be very expensive in my opinion. So as said with out looking at the wagons which are derailing it is not easy to see the problem. But if they are old Hornby with plastic wheels I would bet a wheel change is best solution...........John

[gazzarose]

All of the wheels are brand new that either came in the piece of rolling stock or from the 3 packs of new wheels that I bought to replace any plastic wheels on anything new or old. Everything seems to be running nice now since I fettled the plastic frog with a nail file. 'Thomas' and 'Percy' are currently running round and round running in ready for their big debut on Christmas morning.

[footplate1947]

Well done you got it sorted. Again, ever so often it is something simple. My I ask was it a older Hornby point. john