Tag Archives: coupling rods

Repairing a Bachmann 03 Diesel Shunter


This British Rail Green diesel shunter belongs to my dad. He bought it from the Bachmann discount stand at Warley 2012. The motor seems to stall from time to time and I suggested I would have a look at it. Now 12 months have almost past, I think it is best I take a look.

I remember that the coupling rod appeared to be slightly bent on one of the rear cranks, so I suspected it could be an issue relating to the coupling rods jarring. After a quick run on the rolling road I whipped the body off.

The trickiest thing to do is to slide up the NEM couplings without breaking off the backing. The body screws are located beneath them. I have some special screw drivers designed to work with hexagonal bolts, which are very useful for removing coupling rods from RTR locos. Unfortunately, the pin that fixes in the crank at the back of the model isn’t hexagonal and won’t unscrew. Instead I removed the crank along with the coupling rod and used my ‘hold and fold’ tool to flatten the coupling rod back out. Stalling still seemed to be an issue, so I added a very thin washer beneath the crank to see if that would reduce the play in this area. In addition, I stretched out the pick-ups to increase contact with the wheels. As a final step I swapped around the front and rear axles and screwed the coupling rods back on.

I then set the shunter off at full speed on the rolling road, to see if this would remove any burrs that might be causing issues.

There have been no signs of stalling since. It was quite simple to create the stalling effect before the modifications, so maybe, just maybe I have sorted it out.