QUOTE (theallendalebranch @ 20 Aug 2008, 10:09)
<{POST_SNAPBACK}>I have had a pair of bachmann 20's before & they struggled to run double-headed as one was a lot faster than the other one (I only operate on DC as I dont yet understand DCC or want to spend money converting everything). I'm more convinced that with Hornbys new super smooth motors that double heading will be a lot more easier.
There's no noticeable performance difference between Hornby''s 'black can' that is pretty much the standard motor on all the new introductions in their range, and the similarly dimensioned Kader can motor that Bachmann use in their diesel models. Model mechanism assemblies do vary quite significantly, and it is here that I would look for the cause: a tight gear tower being top of the list. Have you tried running it continuously for hours, to see if that helps free it up? The other alternative is to strip down the slower mech, identify the cause, and eliminate the tightness. It can be something really minor like a bit of flash on a gear hub, or the gear tower walls having a slight distortion, so that one gear is slightly clamped.
It will be interesting to see what Hornby do with the ex-Lima 20. In Lima's hands it had a centre motor driving a single bogie, and even with a 4:1 gear ratio could be a decent performer. (Lima put in several different types of can motor, one type they used was similar to the Hornby and Bachmann can motors and worked very well - although the gear ratio permitted a top speed scaling over 400mph.) If Hornby simply replace the motor with their black can, maybe adding a flywheel, and making the gear ratio something between 12:1 and 20:1 it will run nicely enough. If they really wanted to, they could alter the chassis casting and have both bogies driven. The other possibility would be the sad regression to a motor bogie...