Peco Curved Turnout Problem Solved

This morning I was free to do a little modelling so the plan was to make some minor modifications to a recalcitrant wagon which refused to go through a couple of my Peco curved turnouts like the rest of my wagons, head up to the layout room to do a quick check of a turnout template I’d printed out from Templot and test the wagon through the curved turnouts on a train. After these small jobs I’d be free to get back to building some turnouts in the work room inside the house. It was at this point that things went awry.

So let’s back up a little and go back about 12 months to a post I made about this same wagon and another Peco turnout that it wouldn’t run through. At that stage I determined that the gauge of the track at the heel of these turnouts widens out to something like 33.3 mm. As the wagons run through the turnout some have a tendency to drop into this gap and derail. At the time I wasn’t having any problems with the other curved turnouts on the layout and they were all pretty much on unsenciked sections so leaving them in place wasn’t an issue. However this one was on the scenicked portion of the layout between Morpeth and QW and as such the simplest solution was to build a hand made equivalent and replace it. Problem solved, or so I thought.

Now jump forward to two or three weeks ago to my 3rd operating session with the Boderline Operators. As soon as the operators started running trains out of the yard they identified wagons that kept derailing at the throat of the yard where there are three of the same type of Peco curved turnout and of course one of these wagons was the little 4 wheel cattle wagon that had given trouble on the turnout that had been replaced. Other wagons occasionally had trouble on these curved turnouts but this one derailed every time. All the wagons giving trouble were removed from the track as the problems occurred and I’ve spent some time since working on them, checking wheels, couplers and back to backs. All the wagons I’ve been working on were put into a train this morning and they all ran through the curved turnouts….except the cattle wagon.

So to be more accurate from my statement earlier in this post that the other curved turnouts on the layout weren’t giving me problems I’d have to say that the other curved turnouts weren’t being used much and as such I was able to ignore the fact that some wagons invariably derail at a particular spot. Because I hardly ever run trains on my own these problems can be shunted to the side. So after having done the required checks on this particular cattle wagon and having determined that the back to back was fine on both wheels sets, the axles were reasonably parallel, that the couplers were at the correct height and had more than enough swing it came back to the turnout. As the wagon was derailing on the heel of the turnout where the switch rails come into contact with the stock rails (the same spot it had derailed on the turnout I’d replaced) it was clear that the real culprit was the 33+mm gauge at this spot and not the wagon at all.

As anyone who has used Peco turnouts of any type you’ll be aware there is a notch ground into the stock rail where the swing rail comes into contact with it. See the red circle. While the object of this exercise is worthy, to ensure that the wheel has a smooth ride through the heel of the turnout, this objective is somewhat superfluous when the gauge widens to over 33mm at the same point.

Generally speaking I’m very happy with the Peco turnouts and track on my layout: most of it works flawlessly and does a great job in the areas where I’m not going to apply scenery and don’t have to try to pretend it looks anything even remotely similar to NSWR track. However I wasn’t at all looking forward to having to rip up the four Peco curved turnouts that lead into the storage sidings and replace them with hand built replacements that would each take me a week to construct. In working on the same problem with the turnout I’d replaced I packed out the notch and soldered some brass into the gap, filed the notch and even hammered in a few extra track pins in an attempt to overcome a small difference in elevation all to no avail. That fussy little cattle wagon would not run through that turnout without derailing.

This morning as I stood next to the layout where the offending turnout is located I reached down in frustration and pushed the rail with my thumbs and it moved. Most Peco track of this type has rather large rail chairs moulded into the plastic base and nothing short of a Dremel and a good bastard file with move it. But because the rail adjacent to the switch rails of a point can’t have rail chairs on the inside of the rail it’s not held quite so securely at this location. I suddenly realized that the offending rail gauge at this very spot might be altered enough by the use of a simple packer.

I took a small rectangle of thin writing paper from a coloured pad that was sitting on the storage sidings (I’d been using it to record all the problems that had cropped up during the operating session) and folded this over twice. After shoving this down between the rail and chairs I tested the trains through the point and there were no derailments running either forward or backward.

Packing the rail in a little with some folded paper pushed it over just enough to solve the problem. It turns out it wasn’t so much the wheel dropping into the gap at the heel of the turnout that was the problem but that the wheel (especially on my cattle wagon) would round the fairly gentle curve of the turnout with the outside wheel flange hard up against the outside rail and when it hit the notch the amount of slop in the gauge at this point would allow the flange to catch and let it ride up onto the top of the rail. I tested the train back and forth through the turnout 4 or 5 times with no derailments. I’ll determine the best amount of packing to insert and replace the paper with some styrene and glue this in place once I check that the problem is cured. My guess would be that something between .020 should be more than sufficient.

And just to prove that it really did work here’s a little video of the train working it’s way through the turnout. The cattle wagon mentioned in the text is the last wagon in the train.

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