On Saturday, as Flockburgh was set up, I took the chance to tinker with the 2F locomotive I rebuilt some time ago. It wasn't running very as well as it should after all the effort that I'd gone to reworking the iffy solid chassis to a super-dooper compensated one.
On the track, the model stuttered and advanced in a series of jerks rather than the hoped for silky smoothness. I prodded the pick-ups and improved things a little but it was still as pointless as putting lipstick on a pig. More drastic measures were called for.
First the chassis was tested sans body. Once I put some weight over the front end courtesy of an old crab fishing lead lump, things worked very much better. Apart from the out of gauge weight whacking the water crane, running was nearly as good as I wanted. Putting the body back on, things degenerated again. At least I had an idea where the problem was.
On the bench, off came the body. The bits of lead weight came out of the boiler and were replaced with some "Liquid Lead" to get as much mass as possible over the front. This was secured with drops of superglue as the lead reacts with PVA and expands over time causing the locomotives to explode in slow motion.
The chassis got an extra set of pickups on the powered axle. I'd only fitted the front two with them before. Those already in place were tweaked to keep then in touch with the wheel rims at all positions of the wheel.
Testing looked promising until the glue joint holding the final drive gear gave up. Another dollop of superglue fixed this and all appeared to be well. A bit of running on the layout showed promise so the loco could take it's place back on the passenger train - my "running in" turn on the layout.
During the show things were OK most of the time but occasionally the loco wouldn't stop dead a refuse to move forward. A little reverse seemed to sure this and normal service was resumed. OK the running still wasn't great but it did appear to be improving. I put this down to the various bits of metal bedding in properly, especially the hornblocks which I never seem to get perfect. If I'd used Romford wheels I'd have assumed that the crank pins were unscrewing or tightening up, but with these wheels that's not a possibility. Pity, I know how to fix the Romfords...
By the end of the day attention is obviously still required. One thing I spotted was that the ends of the crank pins were shiny. Now this is probably due to handling but might just point to them rubbing on the inside of the valance at the top of rotation. I'll get me magnifying glass out and take a look sometime.