Home > Installations > Installations in 4mm > Customer Installation Report - Jon Fardell - 4mm Gauge Bachmann Class 105

Text and Photographs (c) 2016 Jon Fardell

Jon writes: I was asked if I would do a short write-up for the Newsletter about my experience with Protocab, particularly the loco installations.

A few months back I decided to return to 4mm scale after a gap of around 55 years. In the intervening period I have been modelling R/C model aircraft, particularly electric powered, and latterly Gauge 1 R/C battery electric in the garden. So I know very well the benefits of being able to drive locos on electric-free track. I decided to model a simple end-to-end layout on the old GN station in Hertford, where I grew up. I was just about to order the necessary DCC items to get started when I saw a piece in RM magazine describing the Protocab system, which fitted in very well with my G1 experience. After a few days thinking about it I decided to give it a go and ordered the ‘Bundle’ with the small battery, and I have to say I am very pleased with it.

The prototypical list of locos for my era/layout is rather short – J69 tank, N7 tank, and 08 shunter. All rather small for a first attempt. However, I found a photo of a Cravens DMU on a rail tour in 1959 that visited the site which I thought would provide plenty of room for the installation, even if some of the seating had to be sacrificed. A Bachmann Class 105 was duly obtained and I removed the two PCBs with all the connections for pick-ups, directional lighting etc, together with the lighting strip in the roof.

Photograph (c) 2016 Jon Fardell

I initially laid out the charging unit, Locoswitch, LCU and battery on top of the motor mount/weight that is in the guards/ luggage area but soon realised that there would be problems with the charging unit and the Locoswitch if the body was to be removable.

The solution was to turn the body up-side-down and fix everything in the roof, with the charging unit against the end with the hole for the plug right up against the roof above the corridor connection.

The PCB width has to be reduced to allow the socket to fit tight up against the roof, but even so I had to notch the large plastic shroud on the plug to clear the corridor connection. The glazing in the end of the unit makes the small hole for the LED unnecessary. The LCU can be stuck directly to the roof with its heat resisting pad, which in fact is not very sticky so I put a couple of thin plastikard strips across to stop it falling off. The Locoswitch is stuck directly to the roof, and I had some very sticky double sided automotive foam tape that held the battery, but I also put the plastikard strips across just in case.

Photograph (c) 2016 Jon Fardell

All this fits neatly in the roof above the windows and is not seen from normal viewing angles. If the motor leads are kept long the body can be easily removed and laid alongside the chassis without disconnecting anything. Anyway, it all worked perfectly ‘straight out of the box’ with all the interior detailing as Bachmann made it.

So onto the next challenge – the J69, and unfortunately no rtr model available. The is a Wills white metal kit, and I did make a couple of white metal kits for a work colleague may years ago which I very much enjoyed, but I thought if I got bogged down building locos I would never get anywhere with the layout. So I decided the recently introduced Hornby J50 would be a reasonable, if incorrect, substitute. I did ponder a bit over the decision to buy one as I had no idea how much space there would be in the body, but luckily there was an article in the Hornby mag. about fitting sound which did show that the motor was right up in the smoke box area and provision had been made for one of the tank weights to be removable for a decoder and there was space between the motor and cab for a loudspeaker. I decided to go for it, but in the event I really had to fight for the last 0.5 of a millimetre to get everything in.

I had hoped to use the bunker for the battery, but there is a massive lump of metal on the end of the chassis that takes up most of it and I didn’t fancy cutting it off. Even so the other tank weight has to be persuaded to come out and the cab floor, most of the backhead, and various bits of plastic have to be carved out of the body with a diamond mini disc to get sufficient space. I made a plastikard false cab floor that fits just under the window sills with the battery and LCU mounted below. There is still a bit of backhead left and with the floor painted matt black it is not particularly noticeable, and I think with the upper parts of a driver and fireman mounted on it nobody would see it. The charging unit is in one of the tanks with the hole facing up which I will disguise with a mushroom vent.

I connected it all up and screwed the chassis back and I have to say switched on with some trepidation, but needless to say it worked perfectly.

Photograph (c) 2016 Jon Fardell

With all the connections it is extremely tight and the components are much closer together than I would have preferred. Doing it again I might sacrifice the whole of the cab interior.

However what is truly amazing to me is the way it will creep along the track at an ultra slow snail’s pace with absolutely no sign of sticking. I was surprised at the Ally Pally show this year how many of the fabulous exhibition layouts required locos to be poked with a finger to get them going.

I think I would advise anyone wanting to install Protocab in a small rtr loco to look at the more recent issues where the designers have realised the people might want to fit decoders and sound etc and moved things around a bit to provide sufficient space. The other way round this problem is to do what they did in the early days of G1 battery electric and fit everything in brake or box van semi permanently connected to the loco with extended motor wires between the two. A bit of a compromise, but it gets over the problem.

I need an N7 for my layout, but with no rtr model available, it will have to be the Wills kit. This may in fact help because with a metal body no additional weight will be necessary and I will be able to chose and locate a nice small motor to give the maximum space. We shall see.

(*Thank you to Jon for this excellent write-up. - Ed)