Wheels of Progress

After the Railway Maintenance Working Party had done such sterling work in wheel cleaning Al had taken the cleaned locos and run them around our layout. One of our pride and joys is an old Tri-ang R653 loco, a 2-6-2 SNCF black steam model (a Continental “prairie” model from the 1960’s). It’s the most majestic looking loco we have (Al would probably vote for the Hitachi bullet train, but I am an old enough fogey to feel nostalgia for the steam engine!). It was the last of the three cleaned locos to be test run, and he called me in to show it running. But - it stopped. 

A Tri-ang R653, a Continental Prairie in French livery

Now there are lots of possible reasons for the stoppage. It was stopping near to some points. One of the constructional differences between original Tri-ang and modern Hornby is that the track is smaller in height. It is more “finescale” in the jargon. The flanges on the wheels (the bigger bits that drop down to the side of the rail) were made to suit older higher track. When a Tri-ang loco goes over a point there is a piece in the middle – called the “frog” where the two running lines come to meet. The groove in these frogs is not deep enough for the depth of the flanges on most Tri-ang locos. This means the main wheel is lifted up and loses contact with the rail – reducing the transfer of power from the rail to the engine. This usually results in a “stutter” in the running of the engines around the track.  Since the problem appeared to be happening just after the points, I wondered if that was the cause. We ran the loco a few more times.

If you look carefully you can see the dirt on the wheels.You can
also see the deep flange which makes it difficult to run on modern track

Yes that’s right – we ran it again – even though it had stopped. What we found was that if we turned off the Hornby power controller for about a minute, it seemed to reset things so that it could run the loco again. And on the next test run , the loco stopped again, but nowhere near the points. The way our weekends go we didn’t have time to do any more testing, so the problem remains a mystery at the moment. I am wondering if the engine is somehow building up electrical resistance so that eventually the power controller cuts out. This does seem to be a feature of the Hornby rail controller. More research is called for – but that’s going to mean finding some more time to spend at the trackside!