Introduction

JLTRT 7mm diesel kits have been around for some time now, and they have certainly set a high standard, utilising new technology for their design and production. Examples on their display stand at exhibitions are most impressive and inspirational. Great use has been made of resin for the main components. There were a number of kits incorporating this material available in my 4mm modelling days, but I hadn’t built any myself, all the locos I built were of brass or white metal, so this was a new experience for me. Also extensive use of superglue in the construction was a significant departure from my earlier kit building experience; most of my previous construction work has been with solder and Evostick, superglue only being used in certain limited circumstances. So the effectiveness of cyanoacrylate was still to be proven from my point of view. The kits could be regarded as expensive, but on opening the box and examining the mouldings, they were found to be of superb quality, with little cleaning up required. That’s what you are paying for I suppose. Most of the ‘making’ has been done with the quality pattern work, and it’s just a question of carefully assembling the parts. I believe that the full size locomotive is scanned in to a computer and the kit masters are derived from that. This would account for the accurate appearance of the models.

I had purchased both class 24 and class 25 kits. I was fond of these types, the 25s were local to North London in my trainspotting days in the early 70s. 24s were viewed as a little more exotic having moved away from London by that time. They were dwindling in numbers but I caught up with them when on holiday on occasion in Pwllheli, North Wales. I clearly remembered watching one shunting Pwllheli goods yard from my uncles’ house on the hill above the railway – that seems like a thousand years ago!

5 components make up the locomotives, cabs, sides and roof. None of the parts are common to the 24 and 25. No glue has been applied yet…

Infinite detail variations seem to exist, as with any locomotive class. So some background research is enjoyable time spent, engine picking and well worthwhile. What surprised me was that comparing the class 24 and 25 body parts from the kits – none were the same – all the parts are different between both classes. Pretty well every variant is catered for by JLTRT, which must mean five or six different sets of sides. The Ian Allan Diesels in Depth Classes 24/25 book is an ideal source of reference to explore the endless variations in detail. There is also a very good web site, www.derbysulzers.com, with detailed history of individual locomotives and plenty of photos.

Assembling the body

There are fully illustrated instructions, and there is little point in me re-writing those in this instance. I always read them through first these days and there is some good advice therein. There are some points I’d like to add though, that could certainly be helpful for other builders. Work starts with the cabs and these are well moulded with good detail. The main work being to clean up the insides of the window rebates and drill holes for the various fittings. I wanted to fit the tail light lenses and decided to use 2mm LEDs for these (albeit non-working). These could be masked with Maskol for the duration of the painting process. So the backs of the light housings were carefully drilled to accommodate them. Fitting the windows came next (they are masked up for painting) and early sets of instructions suggest the use of ZAP CA. With good ventilation and a steady hand this is probably possible, but I struggled with fogging on some of them. They are laser cut and fit very well, but I wasn’t fully satisfied with my efforts. JLTRT very kindly forwarded some replacements and more recent instructions advise using canopy glue – from the model aircraft hobby. I found that watering it down a little allowed it to run into the window rebate. It was then allowed to set overnight. It works well, dries clear and can be rubbed off the window surface if necessary without any damage. More recently on other projects, I have used ‘Glue and Glaze’ which is very effective. The cab interiors were made up and painted also at this early stage. I departed from the instructions (a Brian Daniels idea) in that I attached the bodysides to the chassis at the stage where the roof is glued on. Using a squared Plastikard template as advised is probably the correct way - but the way I did it worked, the body would then fit perfectly to the chassis. The less glue the better really, not much is required at all to get a good strong join. There is really not much to do to the actual body. Just a check for fit and some minor cleaning up to ensure the sides fit well to the roof. The etched fan grill is made up using a jig and that completes the main body work. As it says in the instructions, the ends of the sides need gently trimming to ensure that the cab fits perfectly.

Class 25 cabs with the details added. They are easier to work on before they are attached to the body

Before I fitted the cabs to the body, I masked up the windows ready for spraying, on the basis that if I over enthusiastically pressed on the tape it would be easy enough to glue the window back in whilst there was still good access. They are pretty difficult to get at once the cab is on the body. I have noticed that other builders have craftily modified the cab bulkhead to make it removable, as designed it has lugs that fit into rebates in the sides and once fitted in will never come out. The class 24 has the buffer beam moulded as part of the cab and it’s probably easier to fit all the pipes and other bits at that time.

The made up and painted cab interiors, a nice little painting exercise. Recently I’ve seen people making up all the internal signs and adding them. I’m afraid mine are lacking.

Assembling the bogies.

The design of the bogies requires screwing the motor directly to the frame. Rumours abound in any hobby and I discounted any stories of resin bogies melting when the motors got hot, not hearing of any first hand. However I wanted more control over the motor/axle relationship and opted to use the Markits MM1 gearbox. A rectangular hole needs to be cut in the bogie top to allow the motor to pass through. This was achieved by drilling four holes, one in each corner, and using a piercing saw to join them up. I had to reduce the width of the Delrin drive cog to allow it to co-exist with the drive gear, and mounted the gearbox bearings on the outsides of the gearbox to maximise the space inside. I’m not saying the design of the kit is wrong or right, this is just how I chose to do it. It doesn’t say in the instructions, but it’s probably best to glue the axle bearings in place. If one were to stick on the axle, it might cause problems with the resin frame. I also found that the Delrin cog teeth on the outer wheelset were very close to the inside surface of the frame, so I used a large drill twisted by hand to create a recess above it to give some clearance.

One feature I don’t like about the design is that the sideframes are designed to be permanently glued in place, meaning that the wheel sets are permanently trapped. Later JLTRT designs, such as 10000/1 feature outriggers from the frame that the sides screw on to. I prefer to be able to get the wheels out if necessary, so I drilled 0.7 mm holes through the end frames into the side frames and used push fit brass pins to hold the side frames in place. Some of the detail components glue to both parts, but these are small area surface joins that could be split apart and remade if necessary. The detailing of the bogies took place over a couple of weeks during the evenings. This again is a departure from previous kit building experience, by comparison, the bodies were assembled in one evening.

The main bogie frame, with an opening cut to allow the motor to mount on the Markits gearbox. I added flywheels later.

Brass bins were push fitted into drilled holes to retain the bogie side frames. The frames can be dismantled later on if any maintenance is required.

The majority of the fittings are lost wax brass and cast to a high standard. There was little cleaning up work to do. With four bogies there was a lot of repetitive work to do, that meant there were 16 brake pull assemblies to clean up and fit. When I came to fit the last side frame, I discovered I had two driver’s side frames for the last bogie unless I had made one with two diagonally opposite sandboxes. An E-mail to JLRTRT saw some replacement parts arrive in the post after a few days – excellent after sales service. The penultimate task on the bogies was to add the pipe work along the sides. The instructions suggest plastic rod or brass wire. Plastic rod was out as I didn’t have any and my attempt with brass wire was poor. It was too stiff to follow the contours of the side frame. In the end I used 0.45 mm tinned copper wire. This is normally regarded as too soft for this sort of work, but after stretching it to straighten it, was ideal for shaping to follow its winding path along the bogie side. But how to retain it? There are four clips that can be seen in prototype photos. Initially I drilled 0.5mm holes and made brass wire hooks, but even with the outer face file flat, the clips looked like what they were – wire.

After sitting and contemplating my untidy workbench I noticed the nickel-silver half etch offcuts from the step etches. They looked more like the sort of material to represent a flat steel clip. They were just slightly wider than the holes and very thin, so could be forced in and then bent carefully over the wire. It worked. I spent the next 10 minutes rummaging through the bin like a detective to collect all of the other offcuts and managed to salvage enough to do all four bogies.

Underside view of the bogie, showing Slaters pickups, Delrin drive chain and Markits gearbox.

A side view of the completed bogie, all the brass parts were glued on with ZAP CA. Diesel bogies have a lot of detail and it’s great to see that all properly represented.

Making up the bogie steps, it is easier to do this whilst they are still in the fret as they are pretty fragile.

The last task was the steps. For strength I decided to drill and pin them to the bogies with 0.6mm brass wire. Half etch indents are provided on the step mounting tabs, and these were drilled accordingly before starting to assemble them. As suggested in the instructions I made them up with one side still in the fret. Significant points to remember: - the tops of the vertical side rails are rounded, the bottom edge squared off, the mounting tabs of the door steps all point in the same direction – right for the driver’s side – left for the second man’s side, steps project outwards. The first set assembled well, the second set might have been in the etch bath slightly too long as the midway point where the etched holes are for the middle step was very weak until re-enforced with solder. Anyway, with some care and patience they were assembled satisfactorily. I mounted each step individually – i.e. used it as a template to drill the holes and fitted it in place before moving on to the next. Some tweaking is required to get them to fit just right but the top of the bogie frame and the axle box cut out in the frame can be used as alignment guides. They need to be as square as possible, otherwise they will stand out as not square and look awful. Once finished, the bogies look very, very good. The second last task! Moulded blocks are provided on the side frames to mount the steps to facilitate access up the side of the locomotive to the roof top water filler. All my side frames had these – although photos in the instructions show side frames without them. It was a simple matter to carve off and clean up the unwanted ones. One thing I would like to have done was to drill the distinctive lightening holes in the wheels, but without a pillar drill I couldn’t think of a way to do it neatly.

The Chassis

The chassis is a one piece moulding and on the Class 25, where underfloor fittings are more exposed, the draw gear and connection hoses are fitted to the bufferbeam as part of that moulding. On the class 24 where the fittings were more modestly hidden behind skirts, the buffer beam forms part of the cab moulding.

Although the instructions suggest painting and fitting them later, I personally prefer to do as much fitting as possible before painting. So the hoses and connections were fitted with the cab loose. I was unsure about the AWS bang plate and had almost decided to fit them throughout, however after some research, I found that the AWS pick up is only at the Number one end. So the bang plate is only required at the number one end, with just the tank and bracket at the other. The set of steps for the buffer beam are designed to be butt glued on to the buffer beam. To make it more robust, I drilled out the top bolt head and substituted it with 0.6mm brass wire that fitted into holes drilled in the beam. The class 25 has some distinctive pipework, often painted white, beneath the cabside on the driver’s side, so I added a representation of this with some sections of brass wire.

The battery boxes and water tanks come as one piece mouldings, again with little cleaning up to do. The various fitting holes were drilled out with a 1mm drill and the necessary lost wax parts were cleaned up and fitted with Zap CA. All very easy. Supplied with the kit was a long M3.5 screw and force fit bush to hold the assembly to the underside of the floor. I didn’t feel there was sufficient meat in the floor to hold the bush, so I soldered a 4BA nut to some scrap brass and glued that to the floor with Evostick and a suitable screw holds the battery box assemblies in place.

The class 25 awaiting the paintshop. Brass models look great in the raw, I think this will look much better painted…

Painting and final detailing This actually turned out to be a quite a task due to the four basic colours used on the body, and the repeated masking and unmasking.

This was the basic sequence, I used spray cans.

• Apply Halfords grey primer

• Mask off the warning panels

• Apply green body colour

• Remove masking

• Mask everything but the warning panels

• Apply Yellow for the warning panels

• Remove masking

• Mask body to allow white bands to be sprayed, mask roof too

• Apply white bands

• Mask all of body

• Apply roof grey

• Remove masking

• Touch in overspray and correct errors by hand brushing

I used JLTRT colours for the green body colour and yellow panels. I masked off the yellow panels when spraying the main body colour, so that they remained in undercoat grey in the hope that the yellow would cover better. I mixed up a dark grey from enamels for the roofs. Although many photos show a light grey roof, numerous colour pictures of the locos in the early sixties show them with a darker roof, the depot staff must have given up trying to keep them clean. A few engines on carriage duties must have been through the washing plant as the body side and lower part of the roof appear to be clean in some examples. My locos will be employed on mineral working, so won’t have been near a carriage washer for a while. The weathering will reflect this.

The numbers and lettering came from the Fox Transfers range and I used photos of the particular locos I was modelling. There are numerous subtle differences in the positioning of items such as warning flashes. It’s worth the effort to get it right. Once I was happy with the transfers I sprayed a coat of Precision satin varnish over the loco bodies, the roofs were masked off this time. Painting the details, such as pipe connectors and handrails seemed to take an age, and the JLTRT advice is right – it is easier to paint some components before adding them.

The moment of truth – removing masking after spraying the roofs. Often a nervy experience.

A comparison of the front ends, they are pleasing models. Even some of my hardened steam mates have been tempted.

I ran into problems with the Class 24 handrails.

A start on the weathering, the window masking is still in place, but that realism is starting to show.

The etched holes didn’t match the mounting points on the bodyside, so I drilled new mounting holes for the lower fixing point and filled the redundant ones with solder. Adding the mounting wire and this alteration is all best done with them still in the fret. They also seemed a little wide as etched, so I filed some material off each side to reduce their width. They certainly look better for that.

It’s possible to make the Class 24 headcode discs work. It was a bit of a fiddle and some of mine probably would, if they weren’t gummed up with paint! I set the code for mineral traffic, the allotted task for my engine. I was going to use Fox headcode letters for the class 25, but they are 7mm or so in height and wouldn’t fit inside the 6mm high headcode box. I scoured my transfer collection and the various transfer suppliers but couldn’t find 6mm ones, so I ended up making the codes up on the computer in Microsoft Word using Ariel font, which was the closest I could find. Not all of the characters match the prototype ones, so I was selective in their use. I filed the ‘glass’ for the boxes to be a tight fit, so they are not glued and could be carefully pinged out at a later date to change the codes. Again, I chose codes suitable for mineral traffic.

After allowing a good time for the varnish to dry I mixed up some thinned weathering mix to paint into the grills. This was brushed in and then wiped off. It looked messy, but better when dry. A blow over of slightly darkened Humbrol Matt 62 leather, with more intensity on the lower body sides represents brake dust dirt. Matt black was gently sprayed around the exhaust ports. At this stage the locos were finally starting to look finished and I carefully removed the masking from the windows. The remaining work was to add the lost wax windscreen wipers previously dipped in blackening agent and to add a little more detailed weathering by brush. Almost the very last items to be added were the bufferheads that had also been chemically blackened.

Conclusion

It’s very rewarding to build high quality kits such as these. It was a distinct change of construction methods of course, compared with working in brass or white metal, and felt more like assembly than construction at times, but it was most enjoyable and gave quick results. You probably could build one in a weekend as some have suggested, it’s the painting that takes the time, and that cannot be rushed. The main contrast with this project to others is that I felt construction was only around a quarter of the work, with the rest spent on the painting process. The quality of the components is very good, with little cleaning up required. The final result is superb – they really capture the appearance of the prototypes that they represent. Although they might be considered expensive, I think that they are value for money, I guess you are paying for the craftsmanship that goes into creating the original masters. I also found the after sales service to be very good. Great fun to build and they look the part.

D5183, with its less glamorous crew, and in a grubby workaday condition.

Sources www.derbysulzers.com Diesels in Depth Classes 24/25 by David Clarke – Ian Allan