Tuesday, April 10, 2007

Repairing the railcar

This model's always been troublesome. I sent it away to be repaired once and it worked again for a while. When it seized up a second time I gave up on it.

With a central motor driving both bogies, electrical pick-up from all wheels, lots of weight at both ends and a 5-pole motor (one of Farish's earliest ones as I remember) it ought to run beautifully.

As I take it apart and check the components the first obvious thing is the gearwheel on one of the shafts.

The teeth are almost triangular from wear on one side. This is the shaft that keeps seizing up. I put it back together without this shaft, but with just one driving bogie it only moves happily in one direction.

By the time I've forced the bogies out and back in a couple of times the pick-up wipers are bent out of shape. I need a more reliable method of current collection.

I solder this thin flexible wire to the pick-ups on each side of each bogie.

One wire is connected to the metal strip under the chassis, the other to the clip that keeps the carbon brush in place (I couldn't get the solder to take on the heavy steel of the chassis). At least all wheels were now collecting current.

Even with the drive shaft removed the motor was still getting stuck. Eventually I realised that the circular parts around the motor could move, and were pressing in on the motor preventing it from turning.

With the flat part in a vice I forced the circular section out by about a millimetre.

Solved that one, and suddenly I saw what was in front of me all the time. The gearwheel teeth were wearing away on one side because the gears weren't aligned. Pushing the corresponding wheel back along the motor axle gave a much better mesh.

I've always liked this model, and its great to have it running again, hopefully for longer this time.

Monday, April 09, 2007

Salvaging my AL6

My first N-gauge loco was the Lima AL6 (now class 86), probably around 1971, for £3.75.

It stopped working many years ago and I never found out why.

The big blob in the centre is an early attempt at adding weight.

I don't even remember what I was trying to do with those wires.

But not to worry. Once I've removed the motor bogie it's very obvious what the problem is.

The wires from the pickup bogie are soldered to the brass blocks. The springs transfer the current from the blocks to the motor terminals. One of the springs has got displaced.

Amazingly, with the spring adjusted the motor starts to turn for the first time in over 30 years.

Of course there's 30 years of dirt to be cleared out.

And the chassis is a write-off. Looks like it melted while I was weighting it down with solder.

But the pickup bogie is interesting, with its sprung axles. With a good clean-up this has potential .

Puttting it all back together the chassis runs fairly well. With extra weight over the pickup bogie it's better, but I don't know how much longer the plastic gearwheels will last.

So, what to do now? I'd like to try a simple scratchbuilt body and chassis if I can find a prototype...