very basic question

[Wellwhynot]

Does a tender drive loco pick up its power from the loco wheels or the tender, reason i ask is i have just bought a new old stock tender drive which runs perfect but if i stop it it needs a gentle nudge to restart, what is the most likely cause of this

[NWR-Gordon-4]

I expect the locomotive and the tender will both have pick-ups. I suggest you pick the loco up and turn it around a take a close look at the chassis, of the locomotive and tender.

 

GNR-Gordon-4 (HF)

[Iliketransport]

Some have Loco and Tender pickups whilst others have one or the other. I also recommend what GNR Gordon said. Sometimes a loose connection could cause issues.

[LCDR]

Some tender drives have traction tyres which will impede pick up on that side, in this case reliable operation will only occur with the locomotive attached.  It is usual for tender drive to pick up from one rail and the loco on the other (or sometimes both sides) the power crosses from loco to tender via the coupling. Couplings may have one wiper or two, which will be governed by whether the loco picks up or on both sides or not. 

 

Misalignment of the wipers on the coupling may result in the whole thing failing, and needs to be looked after carefully.

 

Some loco drive locomotives also have pick ups on the tender. More recently the power transfers by either a plug connection or permanent wiring. 

[morairamike]

I bought a second hand Evening Star 9F. It is tender drive. In its original state it ran but was not the best at slow speed or starting. Please read onto to the end it may help you.

Firstly it had a 3 pole armature which was a jerky runner. I was able to find on eBay a 5 pole armature that fitted straight in without the need to change the housing bearing. That helped a lot with the running and I was able to fit a decoder and achieve slow running. BUT and it's a big BUT it would stall on Hornby crossovers, investigation showed that this was due to the tender pick up wheels being the same distance apart as the insulated sections on the crossover. Further investigation showed that the left-hand side if the loco is used as pick up the right hand side as return. So how to get out of this. I connected a wire to the right-hand brush on the motor and ran it across the gap into the loco and soldered it to the right hand cylinder slide holder. The wire is barely visible. The result a nigh on perfect runner.

[96RAF]

Some tender drive and older diesel models pickup from one side only at the loco or front bogie (diesel) and the other side at the tender or motor bogie.

 

You can in many cases rework the loco and/or tender or diesel bogies to give pickup from both sides. In this respect look at later versions of the model (download their service sheets from the usual sources) to see if and how it can be done. It is often a simple and satisfying exercise, which will improve your loco running ability.