Bachmann 4-6-0 Battery Conversion

 

I’ve been the owner of three Bachmann 4-6-0 locomotives for about three years now, and very pleased I am with them. They have tremendous haulage capacity without “traction tyres” and are, to my eyes very pretty. There are niggles however, as nothing is perfect. Dismantling and reassembly has to be done extremely carefully, for example, screws becoming cross-threaded will easily strip out threads rendering them useless. I also have found they are very fussy regarding power collection from the track. The LGB diesels in my possession do not suffer from this problem as they have skates fitted.

 

Not wishing to blow £350 on an LGB track cleaner, and then be in hock to that company for spare cleaning wheels, I knocked up a Heath Robinson battery driven train with a scrubbing car and cleaning solution-dispensing car in the formation. The photo shows the train from the rear, consisting of the three Bachmann brake vans. The scrubber is visible on the last vehicle.

 

 

 

The cleaning solution consists of white vinegar, fairy liquid and hot water, followed by thorough rinsing with plain water (using a watering can). This initially worked very well, but it has problems on points and crossings as the Buhler driven rotating scrubber, a Black & Decker “mouse” pad like a pan scourer, gets caught on the wing rails etc., levering it off the track. So another method has had to be found.

 

I thought first of wiring the 4-6-0s tender wheels with plunger type pickups, but I have an LGB steam loco with this arrangement and to be honest it is little better than not having them at all. So then I thought about batteries. When I first started out in the gentle madness of our hobby, I could not conceive of any reason to use battery power. How I sniggered at the so called “battery mafia” on other forums. But seeing my ten wheeler stuttering round an hour after the cleaner had been used convinced me something had to be done. I gave it some thought and enquired on the GSM forum. Several useful posts later from some of the esteemed members on there notably fnrobinson, cubythewater, Carl Hibbs & Rhinochugger, led me to a simple circuit and list of components.

 

So, where to put the batteries and controls? I have seen where the weight has been removed in the engine boiler and replaced by the batteries, but I thought that might involve some ingenuity, so not for me then! The easiest place would be in the tender. I don’t use sound in my locomotives, so out came the already disconnected sound unit and in went the batteries and controls. I laid the batteries on the bottom of the vehicle after a little cutting away of the loudspeaker mountings they fitted perfectly. The photo shows the batteries in situ; I used the two spigots for the sound circuit board to clamp the batteries in position with a piece of plastikard.

I had already decided to remove the plastic coal in the tender and replace it with an oil tank. I could then hide the controls within the tanks construction.

 

The controls are simple:

 

i) Run/Charge, this is a SPDT switch. It is in normal use, the on off switch whereby the battery supply is either directed into the control circuit proper or the charging part of the circuit.

ii) Track/Battery, DPDT, this is to allow running via track power as well as batteries.

iii) Front/Rear lamp, SPDT for loco lighting

iv) Forward/Reverse, DPDT, directional control of the locomotive.

 

The only other things to consider are a speed controller consisting of a potentiometer and the charging socket. These are all attached to a piece of plastikard mounted in the space vacated by the coal This photo shows the rudimentary control panel and my appalling handwriting.

 

 

 

Further to this I provided a fuse between the bogies of the tender.

 

 

Why didn’t I mount the fuse under the cover of the tender top? I have no idea. I perhaps should have.
Unfortunately, I could not find connectors neat enough to connect the six wires required to bridge the engine/tender. (2 from the track, 2 to the motor, and 2 to the front light) So I decided to have them permanently coupled. I was wary of this at first due to handling considerations. I have to carry them around within the house quite a bit at the moment, and thought that carrying both engine and tender would be a bit problematic. But it’s OK as soon as you realise where you can hold them.

I fabricated a lift-off oil tank top complete with a walkway duckboard, breather, and lifting eyes. There are no handrails as the NEBOSH certificates hadn’t come through in the post. The crew consists of the original, slim driver with a Jons People fireman seated atop the tank.

 

 The reason he is seated is due to my perception that firing an oil burning locomotive is much less arduous than a manual coal burner, i.e. I have dispensed with throwing coal around as a means of propulsion. I researched oil firing of steam locomotives to come to this conclusion. The fireman, after raising steam has to check the colour of the exhaust from the chimney to ascertain the correct amount of fuel to be using and I would imagine that this could be adjusted via some sort of valve system. This is surely a bit less energy sapping than throwing tons of coal into a bottomless pit. One thing I did not realise is that the burner flame faces the firebox door; I thought that the burner would be pointing in through the fire doors. Anyway, I digress.

While I had the locomotive to pieces, I took the opportunity to fit a brighter headlight. In retrospect, I don’t think this was a brilliant idea as, every photo I have seen of such lights since, definitely has a yellow hue, whereas the LED I have fitted is white. I am not having the thing to pieces again though!  I hate this bit; getting them back together is an exercise in patience.

 

 

 

I removed the rear light and fitted a “back up” light of smaller size. I got these off the LGB green shunters I bought sometime ago. I also fitted proper steps on the tender. The ones supplied by Bachmann are crude plastic affairs, I  replaced these with ones made out of brass strip bent into an “L” shape and fixed behind approx ¼” square wooden dowel. All three locos are close coupled and I want to fit a fall plate too as soon as I can find a hinge that is thin enough and long enough. The photo shows the six wires, the figure and the revamped steps/solebar. Oh the square patch is the result of a soldering iron accident. The air was blue as  you can imagine. But it does not matter, these are old, third hand, uncared for locos.

 

 

 

I intend fitting a set of rear steps too (the ones up the back of the water tank) as these were not up to much either. Finally, I fitted brass bearings in the bogies of the tender due to the extra weight carried. The Bachmann wheels originally being fitted directly into the plastic bogies.

Circuit

 

Referring to the circuit diagram below:- The potential divider R1/VR1 biases the Darlington pair TR1 to vary the voltage to the motor from 0v to full battery voltage. SPDT1 is the run/ charge changeover switch whereby S1 socket or the motor circuit is connected to the battery. If there is no charger connected, the charge side is regarded as OFF. SPDT2 connects the front or rear light. DPDT1 allows switching between battery power and track power and DPDT2 switches forward and reverse. It is most important that F1 is included in the circuit as close as possible to the batteries. Apparently, these batteries can provide a spectacular display if shorted out. Also TR1 will require a substantial heat sink, I used a bit of scrap aluminium about 6”by 1” coiled up to fit in a smallish space.