Completion of my Bulleid "Leader" project.

My original thread on this build has also currently 'gone missing' with the forum changeover, but everything will sort itself eventually and maybe one of the more knowledgeable Admins might link up the two threads when they have the time. I have to confess that this loco has given me more problems than I ever anticipated, not to mention much 'headscratching' and loss of sleep, mentally going through various snags in my head! Nonetheless, eventually I have prevailed and completed what turns out to be an extremely powerful loco, more than I might have anticipated. The main problem stems from the fact that this loco's bogies have one side of the chassis 'live', not a problem on DC, but something to be very cautious of on DCC, which I use. When I eventually received the wheelsets from "Markits", they were of the type that has one wheel insulated and the other electrically connected to the axle, hence the 'live' chassis. Due to the very small 'open frame' motor used, I opted to motorise both bogies with the intention of using one decoder to control both motors. The build instructions (for DC operation) had one motor terminal butting against the bogie chassis, but for DCC use, this is an absolute 'No-no' as the motor has to be completely isolated. This didn't pose much of a problem, as part of the bogie assembly process was 'experimenting' with insulating spacers to pack the motor such as to give clearance between the twin worm drives and the axles driven gear, so although there wasn't much room to get the feed wire through, the insulating spacers suitably isolated the motor. With that problem sorted, bogie assembly was completed and DC tested for correct operation, and I then sorted the pickups using my 'busbars' method, phosphor-bronze wire used for the actual 'wiper' to the wheels, and this was, it turned out, the "Achilles Heel" of the build.

 

I had continual problems with 'shorting', sometimes the loco would run in one direction, but as soon as it began to move in reverse, my Lenz setup (which is extremely sensitive to 'shorts') would shut off the current. Subsequent testing with my multimeter would then show no fault, and result in much muttering from me! Eventually, the penny dropped, and I realised that what was happening was that on reversing, one or more of the 'wipers' were slipping towards the centre of the wheels, and beyond the insulation layer between wheel and 'tyre', resulting in them touching the metal of the spokes, hence the short circuit. My initial decoder (one of my 'standard fit' Laisdcc ones) took exception to this shorting and eventually expired, the first of more than 30 that I've used to give up the ghost.....only a 'tenner', so no real damage to the wallet! In the end, I decided to use one decoder for each motor, (Laisdcc again) both programmed to the same number, and CV 2 adjusted to give an easy start, and this, together with revising the pickups using 2mm flat brass strip bent and soldered into "L" shapes and soldered to the busbars where the original 'wipers' were, bearing onto the 'tyre' rather than the rim has sorted the problem. After setting up, I put the loco on a short bit of track with no problem in either direction, but then I accidentally allowed it to hitch onto the Hornby '2BIL' just visible behind it in the pic. Unaware that it had hooked on, sending it away resulted in "Leader" dragging the 2BIL easily and unceremoniously up the line, much more powerful than I'd ever have imagined. As a result of this, and being aware that during the trials of "Leader", the 'Southern' borrowed the same 'LNER' Dynamometer car and it's staff used on "Mallards" record breaking run, I have now 'bitten the bullet' and ordered the "Rails" special edition version of this Dynamometer car (£125!!!.....ouch!) with the intention of creating my own cameo "Test Train"......well, why not after all the problems of building it and getting it running, there won't be too many models of "Leader" around! This build was my first experience of using 'one side live' type wheels, as I've normally used the fully insulated ones, you live and learn, so hopefully my experience will be of help to any others modellers using this type of wheelset. This final pic shows the loco running 'No2 end' first, which was the only way the crew would run, as the 'No1' cab end was too hot from the smokebox heat. Also visible is the 'flickering firebox' in the firemans cab, and it's doubtful I'll weather this loco, as it apparently always started a run in a clean condition.
Keith.