Adding Pickups to Your Locos/tenders

[GeraldH]

I've had a lot of success using thin phosphor bronze strip, it's easy to solder and being flat can be glued in place more easily than wire. Most of it can be painted black to disguise it. I've attached a blurry picture of an extra pickup added to a Hornby 0-6-0 motor (there's a bit more about this on pages 12 and 13 of my layout thread). This strip is quite springy and the longer you can make it, the lower the friction on the wheel. I think mine came from Peter's Spares and the thinner one they do is the one to go for, as the thicker one is a bit stiff.

[Bigmet]

I like the idea of PCB + guitar string (Free-at-last). Has anyone tried a similar system for the bogie of an 0-4-4, eg M7 tank? I was also wondering if the wire causes wear on the wheel surfaces...

For this specific application, I think you will find that it's 'very tight' for space above the bogie of an M7. The arrangement on current RTR OO 0-4-4T is bronze wiper pick ups running on the wheelbacks, which fit rather more easily. There's a better way, see last paragraph.

I have both the current Hornby M7 and the recent TMC/Bachmann G5 0-4-4T with this arrangement, and have eased the pressure of the bogie wheel wipers to 'just grazing' to make the most of the limited traction, and to ensure that the bogie wheels always turn when the loco moves.

As for wear, the least of the worries! A tyre pick up gets contaminated with track dirt, and sufficient pressure to maintain reliable contact is only possible on powered wheels in my experience.

Just in case it is of interest, Bachmann's two 0-4-4T of MR and NER design knock all previous models out of the park, because they have a superior constructional plan, in brief, metal body work up front and thus above the coupled wheelbase, plastic body to the rear. The result is that the model's balance point is between the coupled wheels, resulting in reliable traction. I expect the many competitors now working in OO will pick this up quickly and there will be better models of 0-4-2 and 0-4-4T as a result.

The only thing Bachmann missed out is using split axle pick up on the bogie, which would really have iced the cake! Bachmann made a lot of split axle steam models in the past, and the suitable bogie wheels can be repurposed; I have done this some years past on a Hornby M7 with a replacement bogie and it made a big difference to pulling power, combined with internal rearrangement to pack weight in up front instead of the decoder socket. It was a lot of fiddly work though and now Bachmann have proven a 'better way' I'll not be doing that again...

[Davidjpriddle]

Many thanks Bigmet,
I have managed to fit a set of wipers on a small piece of veroboard onto the M7 bogie, and it works well for points and crossovers. Drag is a bit of an issue, but I'll experiment further with that.
I drilled out the rivet holding the bogie onto the mounting arm and replaced it with 1/8" metalthread with washers and nuts to provide spacing and to secure it whilst maintaining movement of the bogie on the mounting arm. For this prototype I used PB wipers on the tyre of the wheel. I'll experiment with guitar string next. The only weight in the engine is in the motor, so i am looking at ways to add some weight in the tank/boiler section without upsetting the balance.

[Bigmet]

'Aha' moment, this is Triang-Hornby's version of the M7, a very different kettle of fish. Never looked at one of these, so general guidance only.

I would saw as much as possible off the mazak chassis block forward of the motor, and pack all the spaces forward of the rear driven axle centreline with lead, carefully shaped to fit in as much as possible. (Solid lead is significantly denser than the mazak from which the chassis block is cast. It does present a contact toxicity hazard, so good hygiene is important, and should not be used if children are going to use this item.)

Alternative ballasting materials such as Tungsten alloy shot are effective and safe and should be considered.

[Davidjpriddle]

Many thanks again; I should have identified the actual model earlier. But your advice confirms my thinking as to weight increase. There is some space, but as you suggest the lead will need moulding to the insides. Fortunately no youngsters will be accessing the engine. May be a few days before I can get back to it though.