Peco diamond crossing - short circuit?

Simon_100
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Peco diamond crossing - short circuit?

#1

Post by Simon_100 »

Hello from me after a long break - long story ... And another numpty question :)

I finally finished laying the track down here in Spain and it all works well, well almost all. I am now using Peco Streamline and some Set-track points for the visible part of the layout alongside plan track from Fleishmann Profitrack. But I have a diamond crossing which I think is Set-track (I bought a batch of points still in their wrapping from a bereaved lady down on the Costas) that is behaving very strangely in that in one direction, Top-right (TR) to Bottom-left (BL) it works perfectly in both directions, whereas the 'other' crossing, TL to BR the engines stall completely as they enter the crossover. Moreover, in reverse, BR to TL, they stall at slow speeds but will cross at higher speeds with just a judder and when running very fast. Not only that I have to nudge the engine right over and away form the crossing, well onto plan track, before it starts again with the power left on throughout!

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Each route has its own power supply and the through line at the top split into two section with isolating fishplates on both +ve and -ve rails. I've photographed the engine at the point where it stall - running tender first TL to BR showing where the pick-up wheels are, i.e. with one axle still on the live rails on the crossing but two others on the dead frogs - I haven't tried with an tender pick-up engine which I suppose might make a 'bridge' across the dead section - but it's the same with a four coupled engine too - and remember that this problem does not occur at all on the TR - BL route and is less of a problem running the other way, in this case chimney first!

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I can conjugate verbs in three languages but electricity baffles me ... My first though was that somehow the track had got dirty during the laying but I've cleaned it both with a 'rubber' and ethanol to no avail. With the same idea I tried three engines in case the first one had some sort of flat spot but that all perform exactly the same. But now I'm thinking that it looks more like a short circuit?

Any ideas highly welcome, especially if they don't include lifting this section of track out!
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Rog (RJ)
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Re: Peco diamond crossing - short circuit?

#2

Post by Rog (RJ) »

Looks like you have a very poor fishplate connection of the upper rail at BR of the crossover which could be causing a loss of power.
Simon_100
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Re: Peco diamond crossing - short circuit?

#3

Post by Simon_100 »

Wow, thanks for that. It was a difficult join to make as the Flexitrack leading away tended to draw the rail along with it. I'll see what I can do,

Thanks!

EDIT: I'll certainly try to improve this next time I'm down at my layout but thinking about is the power source is on the TL side of the crossing so this fishplate is beyond where the problem lies, furthermore once over the crossing the engine power away with no problems ...
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Re: Peco diamond crossing - short circuit?

#4

Post by Walkingthedog »

Only a small thing but you should trim the ends from the sleepers on the flexi where track joins points and crossings instead of trying to slot them in together so the track doesn’t get distorted.
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Brian
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Re: Peco diamond crossing - short circuit?

#5

Post by Brian »

It highly likely that the track is not dead flat throughout all the points and diamond crossing. This would allow the front pick up wheels to ride up fractionally and then they lose contact to the rail on one side. At the same time the middle and rear wheel sets are sitting on the insulated sections.
Easy to prove this, allow the loco to stall and with power still On use a small screwdriver or other metal item or a piece of wire to gently touch rail to front wheel, do this on each side until the loco moves off on its own with the contact of the metal/wire item.
Alternatively, with rail power Off, take a metal 12" inch (300mm) rule and place it narrow edge down along the rail tops of the diamond and the points and then look by eye each time to see if there are any gaps between the rules edge and the rail top. Any gaps will either need packing adding under the sleepers to raise that area or reducing the already in place material that's causing the track rise. :D
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Steve M
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Re: Peco diamond crossing - short circuit?

#6

Post by Steve M »

Adding to Roger’s comment, the joints where the crossing rails meet the Profitrack look as if they are barely making contact - bottom right of the photo.
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Simon_100
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Re: Peco diamond crossing - short circuit?

#7

Post by Simon_100 »

Walkingthedog wrote: Fri Apr 14, 2023 8:40 am Only a small thing but you should trim the ends from the sleepers on the flexi where track joins points and crossings instead of trying to slot them in together so the track doesn’t get distorted.
Good point, the distortion isn't so visible from the standing viewpoint but I guess the trains will wobble a bit, so another little job for the list - Thanks!
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Re: Peco diamond crossing - short circuit?

#8

Post by Simon_100 »

Brian wrote: Fri Apr 14, 2023 9:55 am It highly likely that the track is not dead flat throughout all the points and diamond crossing. This would allow the front pick up wheels to ride up fractionally and then they lose contact to the rail on one side. At the same time the middle and rear wheel sets are sitting on the insulated sections.
Easy to prove this, allow the loco to stall and with power still On use a small screwdriver or other metal item or a piece of wire to gently touch rail to front wheel, do this on each side until the loco moves off on its own with the contact of the metal/wire item.
Alternatively, with rail power Off, take a metal 12" inch (300mm) rule and place it narrow edge down along the rail tops of the diamond and the points and then look by eye each time to see if there are any gaps between the rules edge and the rail top. Any gaps will either need packing adding under the sleepers to raise that area or reducing the already in place material that's causing the track rise. :D
Golly Brian, that looks so intuitively obvious - to the trained eye (ouch!) - that I'm certain it's the case. Experience is a¡everything in this as in so many there maters ... I've got a morning down at the Railway on Monday so I'll check this out then.

Thank you so much :)
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Re: Peco diamond crossing - short circuit?

#9

Post by Simon_100 »

Steve M wrote: Fri Apr 14, 2023 10:43 am Adding to Roger’s comment, the joints where the crossing rails meet the Profitrack look as if they are barely making contact - bottom right of the photo.
It doesn't look too good but the problem is that the fishplate is the original as fixed on the Set-track, otherwise I'd shift it along a a bit with a sharp bradawl and a tap from the hammer ... But I think if I follow so and Walkingthedog's advice (above) about trimming the sleepers on the 'through' track above I may be able to waggle the crossing over to the right a bit. In any even the current is fine 'east' of the crossing.
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Re: Peco diamond crossing - short circuit?

#10

Post by Simon_100 »

So full marks to Mr walkingthedog and to Brain!

Firstly I addressed the issue with the sleepers on the through track, trimming them down as opposed to messing them in with the crossing. And Hey Presto! Greatly enhanced performance with trains running through the crossing at high speed, stalling slightly at media speed and struggling through at slow speed. So there's no inherent problem wit the crossing as such.

Then I wiggled the crossing about a bit trying to edge the offending fishplate that Steve M pointed out but to no avails and in fact I got slightly less good running. Looking more closely I see that a) the crossing is bowed upwards ever so slightly by being forced into the gap between the four adjoining track sections and b) unlike the points there are pre-drilled holes for track pins, one in each track and one in the diamond itself. So next time I'm down I'll take my little hammer and punch, loosen up the surrounding track and carefully pin the crossing until all runs well ...
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