Airfix 14xx 0-4-2t loco

If the chassis castings are the usual Mazak Andy then you'll struggle to solder to it. Best advice I can give is to use solder tags under screws, one on each chassis half or failing that, fabricate some new wiper pickups. If there is enough clearance under the loco, then Araldite a bit of Veroboard or PCB to the chassis underside and solder the wipers to that and forget the plunger pickups.
Keith.

Just had a thought! As you are using DCC, does your control setup have the facility to run DC loco's? On my Lenz setup, if I programme 0000 into the handset, then I can run one DC loco via the handset, something I've never tried, but it's in the handbook. That way, if it's acceptable, you'll save yourself a good bit of pain and work, with a simple solution, just leave the loco as it is.

 

Certainly is Jim, begs the question 'Is it worth the hassle?' I know the loco belongs to Andy's son, and you always want to help and encourage the 'young 'un's', especially your own, and I like a challenge myself, but with Andy's skills in 3D printing, and the fact that Dundee Paul has already printed a full loco, might the best suggestion be to create and print a new chassis? That way, there are no insulation headaches to overcome, a new set of wheels gets rid of the dreaded traction tyres, and you can then fit an up-to-date can motor and make a proper job of it. A lot of work I know, but with the skills Andy already has, he of all people is "the man that can" I reckon.
Keith.

 

You make fair points Andy, and looking at converting this loco might be attempting the impossible or at best a severe headbanging session (nice when you stop!) and even I don't go looking for that kind of hassle if I can avoid it, despite liking a challenge. Not being a GWR fan personally, so no knowledge of what might suit, but are there any other easily available models with a more modern chassis that could be grafted in to replace the existing one, perhaps from another regions tank loco? Might be looked upon as sacrilege perhaps, but if it does the job and Alex is happy with it, who cares what the 'Rivet Counters' might think. Ebay often has a selection of sellers with chassis and I've had a few myself for various projects, just another option that could work in this case.
Keith.

 

Also don't forget the electrolysis that can take place with dis-similar metals such as brass, steel and mazak. Any dampness and the screw can lock solid into the mazak due to electrolytic corrosion, and a loco left in a cold loft could cause this.
Keith.

 

I'm repairing some locos for a mate and the chassis are solid blocks of white metal that I'm hoping to take the current pick up for the chip from. Reading Keiths reply regarding the problems of soldering to mazac I thought I too would drill and tap into the chassis and using an 8BA screw with the wire soldered to it. I should imagine, if I give the screw a rub with some grease or copper slip it will not react so quickly with the Mazac.

Pete.

 

Exactly what I'm thinking Andy. Metal left in a cold loft might well experience condensation on it and the electrolytic action (in the same way as rusting) can cause an expansion between screw and mazak block. I could suggest maybe coating the screw thread with a copper grease (Coppaslip), but that might make things worse with a third metal in the mix.......I'm no chemist or metallurgist, so who knows what might happen.
Keith.

 

Yes mate.

I don't know what to say Keith, you could be right though I imagine it would be quite a while before any problems showed up, personally I reckon it's worth trying as the locos are useless at the moment.

Pete.