Maxitrak Ruston battery loco

I wanted to have a battery powered loco that could be used at a moments notice, and purchased a Ruston kit from Maxitrak. This has a cast aluminium chassis. The wheels are supplied correctly quartered and mounted on their axles. The most time consuming part was positioning the axle bearings so that the coupling rods were able to move freely. The chassis is not sprung, though the front axle is on a pivot to allow for track undulations. I have had no problems at all with this and no derailments.
The loco has a 120W 12V Fracmo motor mounted behind the rear axle, and a model 1QD speed controller from 4QD controllers (which I later replaced - see below). Both were straightforward to mount and adjust. This motor is fine when pulling a couple of adults, but could do with being uprated, particularly as my line has a 1 in 50 gradient. The motor and controller both get quite warm. I chose the loud horn option, mounting this behind the motor, and it sounds very good (and loud!).
The bodywork is made from precut and folded steel sheet which is put together with nuts and bolts. The radiator is cast aluminium. Assembly was generally fine, apart from the control panel which was not cut to the correct size. However I have found Maxitrak to be very helpful and responsive, and this was quickly rectified. The first run went well, and I kept the loco in bare metal for a couple of weeks. Total build time was 4 weekends.
The steel parts were rubbed down with wet and dry paper and thoroughly degreased with dilute washing up liquid before being coated with 3 spray coats of Halfords grey car primer. The aluminium chassis and grill were likewise prepared and hand painted with Hammerite special metal primer. I used Halfords spray paint for the 5 top coats, the colours being Ford royal blue, Ford moondust silver metallic with clear lacquer, and satin black. The wheels and coupling rods were painted with Hammerite xylene based black paint.
I labelled the control panel with white rub down letters, and then sprayed this with satin varnish. The Maxitrak makers plate was stuck on this.
The radiator grill was sprayed matt black, and the Ruston logo picked out with Humbrol silver gloss enanel.
Finally the Ruston gained a name - "Maverick". The namplates were supplied by Maxitrak. The Ruston has been very reliable and is great fun to drive. Top speed downhill on my straight has been clocked using a GPS satellite receiver at 7.9 mph (12.8 km/h) with a bogie wagon and driver. Given that the Ruston is to 1:6 scale, this is a equivalent to a full size (rather unrealistic but who cares!) 47 mph (77 km/h). I am using a standard Halfords HB038 car battery that lasts for at least an afternoon and is then recharged with a fully automatic charger.
"Maverick" has acquired a clip on face which causes great excitement with younger passengers. I took a digital photo of a suitable face, enhanced the colours and printed this to size on an inkjet printer.
The 4QD model 1QD single quadrant speed controller supplied with the Ruston is very basic. If the direction switch is thrown on the move (by a child!) the motor and gears could be damaged, and the braking is very harsh. I decided to replace it with a 4QD model NCC-35-12 four quadrant contoller. This provides very smooth acceleration and regenerative braking, and is pretty much abuse proof. In place of the recommended 10k potentiometer, I used a 6 way rotary switch with 5 resistors chosen by trial and error soldered between the poles, to get the speeds shown in the picture, and a keyswitch for the ignition to allow the loco to be fully imobilised. I also fitted a 3 LED battery condition meter, as I was concerned that I was occasionally running the battery down too far.
There is an option on the controller to limit the reverse speed to half that of forward, but I chose to disable this. The new board and speed selector switch have made a huge difference to the controllability of the loco, and it is now much more child (and adult) friendly and fun to drive. This is the board layout for the 4QD model NCC-35-12 controller. A very informative instruction manual, and lots of other helpful technical information is on the 4QD web site.
Getting underneath the Ruston to oil and check the mechanism is not particularly easy, so I designed a small service jig using 25mm by 50mm timber. The plans are available as both TurboCAD and .gif files. The Ruston is turned upside down and supported by its buffer blocks on bubble wrap on the jig. It can be connected to the battery which sits on the floor to allow the motor to run.
"Maverick" ran faultlessly but after 10 years began to look rather worn. I stripped the loco down and completely rebuilt and repainted her. I took advantage of the rebuild to add a pair of 4mm charging sockets on the rear buffer. This meant the bonnet no longer needed to be removable and was fixed in place with 4mm bolts.
I added a small car light to the top of the radiator to allow night running as well.