A question on how to improve the electrical wheel pickup on Minitrix locos, is the best way to remove the wheels, to enable access to bend down the wheel contract strips so that they make better contact with the wheel? If so is there anything to watch out for when removing the wheels?
If you're looking to improve the contact, I think you'd definitely need to remove the wheels to clean the wheel backs and the contact strips.
Depending on what sort of loco it is, things to watch for:
Britannias, 9Fs: make sure the quartering is correct and aligned for all driving wheels - you'll get a very bumpy ride if it's out! Also make sure the contacts on the pony truck axles are good and clean.
Ivatts: Same applies re quartering and pony truck axles - also make sure not to bend and snap the (very delicate) contacts strips when replacing the wheels.
Warships/Class 27s: Wheel-sets are "handed" - so it matters which way they go in (once wheel is insulated, the other isn't) - so make careful note of how they went in in the first place.
T3s/dock tanks: the middle wheel set is fractionally smaller - this ensures best contact for the front and rear wheelsets which carry the current to both -ve and +ve.