A Lofty Find

I was clearing out the loft over the weekend and came across a box of train bits and pieces. Mainly it had lots of empty boxes, but in amongst them I was delighted to find a Tri-ang instruction leaflet on the Overhead Power Supply system. I wish I had had it when the R257 wasn’t working! Anyway, here is one of the illustrations which shows how the catenary system works better than I could!

The leaflet is actually based around the first catenary system Tri-ang introduced. This has catenary wire made to look like its suspended from a curving cable. The Catenary we’ve got is just a single, plain wire. However from what I’ve seen, the rest of the system is just the same.

Train delayed - Haggis on the track!

We survived the Burns Night, but our test layout didn't. (It was after all on the dinner table, and I didn't think it was quite up to hauling the haggis around the table!). I did manage to catch a few quick camera shots, before it all disappeared. 

Tri-ang R257 on straight section showing catenary

 The first pic shows the train on a straight. You can see how the catenary (overhead wire) sits nicely over the middle of the pantographs. The trouble starts when you drive your train around the bend. 

diagram showing how straight catenary would run on
curved track

Here is a diagram drawn using XtrakCad which shows how a line drawn from centre line at one end of a curve to the centre line at the other end (the black line) actually veers off to the inside of the curve.  The pantographs won’t be able to reach across to this line and so won't collect any power. One alternative would be to split the curve into two – see the red lines. But even this line gets close to the edge line of the pantograph. (This would be the equivalent of the Marklin recommendation for a post every 22.5°).

Tri-ang R257 on curved track showing catenary

The second pic shows the train on a curve. You can see how close the wire is to the edge of the pantograph (where I have added a small yellow arrow). What happens in practice is, unless you get it right, the pantograph slips off the wire. As it is sprung, it extends to its full height, and often continues to pick up power by scrapping along the side of the wire – until CRASH – it hits a post.

As you can see from the video of a couple of posts ago we did manage to get it right. First I had to straighten the individual strands of wire I had bent as a kid. One trick I picked up on the internet was to roll the wire – this shows where the bends actually are. It's quite a painstaking job to bend them back. Our test circuit was built using Tri-ang R483, first radius curves, with three straight sections (R480/R481) on either side of the oval. Without getting every “straight” section of wire really straight, the wire didn't quite meet in the middle. In the end I was able to ease some sections of the wire apart inside the connecting clips. This isn't ideal of course – but it worked!

Tri-ang catenary mast (R419)

One other problem I had was with the mast clips – the little pieces of nylon which hang down from the top of the post. Here is a picture of one of the problem mast clips - if you look carefully you can see the wire is sitting behind the clip. The idea is that you push the wire up into the clip and the nylon springs closed around it, leaving the bottom edge free to touch the pantographs. But several of my old masts - like this one - had clips which just pushed the wire back out and wouldn't grip it. If anyone has any ideas how this might be solved I'd love to hear them.

We now have to work out just how to link in a Tri-ang overhead powered track section can fit into our main layout. We'll let you know if we solve that one!

And in the meantime, the words of Rabbie Burns’ Address to a Haggis are still ringing in my ears – “great Chieftain of the pudding race” – the proof of our pudding was watching the R257 zip around the track using overhead power with head lights blazing!

Live wire running!

Electric Overhead

So our test run worked - finally. In the shot is our Tri-ang R257, capable of running powered from the track or from catenary - the posh name for overhead wires!


Its a great model - but frankly a bit unlikely. One of my discoveries in coming back to train sets is the great divide - between modellers who strive for exact replication of real life, as against most of the kids I know (old pretend kids as well as real kids) for whom the toy's the thing. This model was based on an Australian diesel engine, but Tri-ang added the "pantographs" - the roof top collectors - to make it work with overhead power supplies. 


A couple of weeks ago we took this model to a local train fair. I had finally given up trying to get it to run. There we met Dr John the Train Doctor - very clever at fixing model trains. A friend of his told me that this model was altered by Tri-ang to try and break into the American market, where overhead power was considered essential. He said the Americans didn't take to this model and surplus stock was brought back to the UK. Meanwhile Dr John was checking out the inner workings of the model. The problem, it turned out, was simple - inside the motor there is a wire spring, one side of which is sheathed. The sheath prevents a short circuit - but I hadn't spotted that the sheath had worked itself back so the spring was shorting out the  two sides of the motor. Easily fixed - if you know how. (I plan to come back to the inner workings of the R257 in another posting).


But our problems didn't just end with the train itself. We had enormous problems with setting up the catenary. The wires have to sit above the centre line of the track. That's easy when the track is straight, but on a curve you have to bend the wire by hand to match the radius of the curve. As the train moves around a bend, the pantographs move away from the centre line. If the wire is too close to one side or the other, the pantographs slip past the wire and then - CRASH - the pantographs hit the next catenary mast. I seem to have spent days bending and re-bending the wires to get the curve just right. And now - it works - and its a marvel!


The Tri-ang R257, with "Tri-ang Railway" markings is said to be very rare these days. Catenary sets from Tri-ang are also a bit difficult to track down - ebay had a couple in the last three or four days, but both were incomplete sets. I have always loved this train - and there is something special about seeing it powered from above. My son and daughter have loved working with me to get the whole setup running - and there is something special about that as well!