Now here's a good 'un to mull over.
Gave the Edrig a run yesterday; mainly to try a few relaid track sections. In order to run over the route in both directions, I ran round the train intending to run bunker first. I pushed the transmitter stick over to reverse and opened the regulator. Whoa! the loco moved forward...
On inspection, the reversing lever in the cab had been moved back by the servo, but the link to the reversing gear had bent and the valve hadn't moved into the block.
After cooling down the loco was rolled over and sure enough, the valve would move about 0.5mm then stop; as if being jammed by an obstruction in the valve body. (It would not even go into neutral).
The loco was taken into the workshop, no work carried out, reverser tested again, and operated perfectly!
On being dismantled no obstruction was to be found and the valve spindle appeared fine with just a light lacquer, which was carefully lapped off.
All lines were blown through and the loco run on compressed air. The loco was then re-assembled and test run today without any problems.
A total mystery; nothing like this has happened previously. I have always been generous with oiling round prior to running, so it wasn't a seize up- especially since the valve did move freely for 0.5mm.
So, what was it?
My guess is a tiny piece of carbonised oil perhaps...
Over to the Experts...
Dave.