The Master and the Slave (pt1)

I have always been a big fan of diesel shunters. I loved watching little shunters moving around Bescot Yard and the various industrial complexes in the Midlands.

BR Class 13 Diesel Shunter

BR Class 13 at Tinsley. Copyright Mark Addison (from wikipedia)

One shunter I never had the privilege of seeing was the BR Class 13. The Class 13 was a special locomotive, designed to operate over the ‘hump’ in the large marshalling yard at Tinsely. Each one looked like two locos stuck together (which is exactly what they were). Two BR Class 08s were used to create each Class 13 loco. One of them had the cab cut away and was linked, via multiple-working gear, to the other. Thus only one driver was needed to operate these two locomotives; the cabless one being the slave and the cabbed version being the master.

The class 13 was also fitted with large buffer plates which helped counter balance these Siamese locos. Only three were ever created, each with various differences in detail. I saw a model of one on the Rail Express stand at Warley show a few years ago and was eager to try my hand at creating one out of the RTR class 08 models currently available.

First considerations

While visiting the Mickleover Model Railway Show in 2010 I was discussing with a fellow visitor my plans to build a class 13, and how wonderful it would be, having two motors and all, but the chap quickly countered: ‘why use two motors?’ he said ‘wouldn’t it be easier to take one of the motors out’? I must admit, the chap had a good point. I decided that life would be easier if one of the motors was removed, but thought it would be nice to keep the model picking up across both wheel sets.

The two best models to undertake this conversion with are the Hornby and Bachmann 08s. It is apparently easier to modify the Hornby 08 (as it is easier to remove the cab area). Plus the Hornby version is regarded as a superior model. Unfortunately, superiority comes at a price out of my budget range, so I stuck with the Bachmann models.

In October 2010 I came across the perfect donor locos in the form of x2 Bachmann models (08623 and 08672), and so armed with a photocopy of an old Rail Express article on creating a class 13 (Feb 04, No.93) I set to work.


Converting the Bachmann 08 into the slave unit.

I started by removing the motor from the slave unit. I soon discovered that if I wanted the slave unit to continue running smoothly I would need to retain the large cast weight that sits under the motor. The motor really, really didn’t want to be parted from the metal casting and became the most difficult job of this project, particularly removing the motor from the small plastic harness surround (see below).


I then began attacking the slave unit cab. Now it is important to know that the cab is in fact a separate moulded item and actually slides off the Bachmann body (with difficulty). This does leave a chunky area of plastic and interior detail in the location of the cab that needs removing with a small hack saw.


Once the cab plastic was removed it was then time to remove a chunky section of metal-chassis casting which sits in the cab area. Once this was removed with a suitable metal hack saw, it was clear that my 08s were starting to resemble a class 13.

I then used modelling putty to fill in the gap in the cab floor and sanded it to a smooth surface, while also smoothing the cut edges of the bonnet. I then removed the buffers and detail from the buffer beams and sanded them down flat (so they could be used to stick the new ‘meaty’ buffer beams to).

Modelling made easy

It was at this stage that 2011 took me off in another direction and although the new buffer beams were designed and made out of plasticard, I never fitted them. The thought of designing the cab bonnet area on the slave unit put me off.

And so by coincidence RT Models decided to create a class 13 conversion kit out of resin, white metal and nickel-silver parts. I quickly purchased the conversion kit and then got back to work on the loco.

The RT Models conversion kit is easy to put together and was quickly glued into the cab area of the slave unit. I decided to use the new buffer beams supplied with the conversion kit because they already have the holes punched out of the casting for buffers and vacuum pipes.


Stability issues

After refitting the wheels to the now motorless slave unit, I realised that my removal of the cab weights meant that the metal cast no longer fixed to the rest of the chassis (I had cut away the screw holes). I solved this issue by adding a motor harness from an old brass kit to the inside of the bonnet (which provided some rigidity to the body and frames).



It is worth noting that although there were only three Class 13s (now long scrapped), my Bachmann models include conflicting mouldings to any of the three prototypes. The main offender being a tool box (or radiator) on my slave unit that was never included on any of the three real locos. I opted to solve this problem by creating a fictional forth loco (rather than scarring the loco with modelling knives). This also allowed me to be more flexible with livery choice and detail. I have also fitted the larger buffers seen on some of the class 13s, which I think give the model a nice ‘chunky’ appearance. I want to model the engine in approximately 1968 condition, so I plan to keep it in BR Blue, but with the number 4503, which will put the loco in the period just before it was renumbered into the TOPS system as the fictional 13004.

What’s next?

I have linked the master and slave units together with a screw link coupling (managing to make the one on the front of the master fully sprung!), so I need to next test how the loco operates over short radius curves and point-work.

In the mean time, here is a video of the 13’s trial run.

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