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SLNCR Railcar B

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David Holman
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A new year and a new project – an attempt to scratchbuild a model of the Sligo Leitrim and Northern Counties Railway’s Railcar B in 7mm scale, 36.75mm gauge.

This afternoon, managed to make the trailing bogie – only a couple of hours work, but four or five times that in terms of thinking. As you can see from the photos, it is mainly made of plastic sheet: 60 thou for the bogie sides and 80 thou for the frame stretcher. The axle boxes are cut down ABS whitemetal of an early LSWR pattern. Decided on plastic partly to reduce weight, but also to speed up the process. Plastikard is so much easier to cut than sheet metal, though 10 thou nickel silver is easily cut with scissors. The tractor unit frames will be nickel silver though.

The bogie is pictured on a print of the plans on our website. Have drawn myself a 7mm scale version, but this has highlighted a number of problems with the original plan. It may well be that printing it has skewed some of the dimensions, as the wheel base of both bogies measures as 8’ 6”, but the given dimension is 8’. Among other contradictions, it shows the overall length as 54’11” over buffers, but this is the length when all the panel lengths are added up. This does correspond to the drawing [220mm], but the overall width, a stated 9’6, measures as 9’ 9 on the drawing. It brings back memories of one of the first coaches I built. It was a 4mm scale LSWR brake third, done from plans in the old Model Railway Constructor which involved cutting out a 10 thou overlay for the panelling. Only when the model was nearly complete did I start to worry that it was looking too big. Checking the scale on the plan revealed it was actually about 4.7mm to the foot. Words such as the one which rhymes with what rowers put their oars in [and how suck is written in the King James bible] were vented with great fluidity, but the mark 2 version somehow got built in half the time…

Anyway, as well as the above dimensions, the plan shows the driving wheels as 2’ 8 and the bogies as 2’ 4. Neither of these are readily available, so have gone for Slaters 3’ drivers and 2’6 wagon wheels for the bogie. Hence am thinking that, even if the wheelbase is only 8’, with proportionally larger wheels it should still look alright. That and the fact that the wheels are half hidden anyway. Nevertheless, measure [at least] twice and cut once, remains my motto – even if I don’t always remember to practice it.

An early problem with the drivers is that they are one eighth inch axles. Slaters do a 34mm back to back in 3/16, but not 1/8. Am waiting to see if they will do a one off for me, but if not will use brass tube to sleeve the wider back to back and bore out the main gear accordingly – the latter for someone down the Club who knows how to use the lathe methinks.

Otherwise, apart from ensuring the articulated trailer tracks properly, there is nothing I haven’t done before. Bodywork will mainly follow the examples of David Jenkinson in Carriage Modelling Made Easy, while I might well do a bit of resin casting for the seats. Exterior livery is well documented, but if anyone knows what the internal colour scheme was, I will be very interested. A case of watch this space – though am not expecting this to be a quick project.

 

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This looks like a really good project. It would appear that the drawing is not drawn entirely to scale, and that only given dimensions should be used. A note given on a lot of drawings is 'Use Given Dimensions Only' in the day before CAD, this gave the Draftsman some licence in accuracy. For a set of cottages I recently made, I drew the cottages in full 1:1 scale on AutoCAD, and then reduced the size of the drawing to 1:76 before printing.

Best of luck with the build. I look forward to seeing this develop.

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Thanks - sounds like good advice. Think I will probably stick with 8' 6 wheelbase though, partly because of the proportions re slightly larger wheels and also because I've spent £14 on a set of profile milled connecting rods. The latter always a key starting point for me when starting a chassis - they go a long way towards eventual good running and con rods are a pain to make as well!

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David, If you would drawings done up on CAD let me know. You would be able to measure directly off the printed drawing.

Any errors or anomalies could be picked up[ on the drawings first. Send me a link to the drawing you are working off, and I'll whip up one. Even if you don't use it, it might be still a worthwhile exercise for others.

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If you think about it 5-600 smackers is not really a lot for a hand crafted [as opposed to factory made] model. Was doing a buildings demo at an exhibition a few years ago & was asked by one bloke if I did commissions. Told him I was still working full time, but if he didn't mind waiting, a building like the one on show had taken me around 80 hours work. Minimum wage at the time was around £5 an hour, so that made it at least a £400 model. Add in materials and research time could easily add another 25%. Note that is minimum wage - so would hope I would have been worth a bit more than that.

While operating a well known, entirely hand built layout a few years ago, we tried to estimate its value for insurance purposes. Built to museum standards, we guessed at around £30 an hour for such craftsmanship and gave up when we'd passed a quarter of a million...

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With 59 on the blighters to do, seemed a good idea to make a couple of masters and get the casting resin out again.

The interior photo in Backtrack Magazine [1995], gives a good idea of the layout, with 11 rows of 3 + 2, then two more doubles by the rear driving cab. The pictures show the process. The masters are plastic sheet [2 layers of 80 thou for the squabs and 40thou for the backs], with 40x10 thou microstrip for the beading. As you can see, these were then stuck to another piece of sheet and a wall of more microstrip built around them. Silicon moulding material was mixed and poured into to this, then left overnight to set. Next day, it was a case of little and often with the casting resin. 2x half teaspoons worth [5ml in all], was all that was needed for each set of seats. This takes 45 mins to set properly, so it look the whole day to run off the 13 sets required.

Next day, sat down with files and sandpaper to tidy up the castings, after which it was a case of fixing the two parts together with cyano. The seats are mounted on strips of 40thou and will be painted before fitting into the model.

Progress on the latter has mainly been a case of research and planning. The sides will be built up in layers, so the glazing can be slid in after painting has been completed. The drive unit is causing a bit of head scratching, because the 3' dia wheels [yes, I know, slightly too big], have 1/8" axles, and Slaters to not do an extended version like they provide for 3/16" axles. Rang them up to see if they could do a couple of specials for me, but seems the process is all computer controlled machinery and a new bit of software would need writing, pushing the price for two axles to about 50 quid...

So Plan B [for railcar B] is required. Currently favouring some brass tubing to act as a sleeve; will cut the axles in half and then araldite them either side of the tube. Eileen's Emporium do a 1/8 - 3/16th brass tube, which is ideal because that means I can use a standard gearbox. Ensuring the drivers can be quartered properly is the tricky bit. There are various solutions, so will let you know how I get on.

Other pictures show how I do my planning - a drawing is the starting point, but pictures need scrutinising and I make a lot of notes and sketches as I go along, hopefully ensuring mistakes are kept to a minimum. Doesn't mean there won't be rather too many though - and a lot of rude words to with them. Life is complicated - that's why it is fun, allegedly. Apologies that the pictures are in the wrong order.

 

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An auspicious moment this afternoon, as the railcar’s tractor unit ran under its own power for the first time. Only 4 coupled wheels, but a lengthy process getting there, which has taken me out of my comfort zone and learning some new techniques.

A key issue was the fact that the Slaters wheels, being small diameter come on a 1/8” axles, for which there is no broad gauge version available. The answer was to cut the axles in half and then lengthen them with some brass tube. Eileen’s Emporium do a 1/8-3/16” tube, which is ideal because that means a standard 7mm scale gear box can be used. However, the axles have squared ends, important for quartering coupled drivers, so the problem was how to ensure this worked in extended form.

After much thought, realised that my wheels, being disc rather than spoked, had two holes at 180 degrees. At 2mm diameter, I also had some brass rod of this size, so I threaded two lengths through the holes and these held the quartering while slow setting Araldyte was used to glue everything in place. The last pictures shows the axles in a set of plastic frames, quickly put together to check alignment.

Initially made the extension tube too long, so it later had to be filed back. This was because I now needed to use some sort of hornblock system, or the motor/gearbox would have been a permanent fixture in the chassis. A bit of research on the web turned up the excellent High Level Kits version. A quick phonecall got the etchings to me inside a couple of days. They are very easy to fold up, but I did not have any 1/8 axles alignment jigs, so made my own from some silver steel rods in a block of wood.

The distance between the axles was easy as had previously bought a set of profile milled coupling rods. These were used both to mark out the side frames and the axle jig. After that, things went together fairly well. Frames were cut out from brass strip with a piercing saw and soldered together using my new York Model Company magnetic jig, which hold things at right angles while you apply heat or glue.

Fitting the motor gearbox came next & then epoxyed some PCB strip to the outside of the frames and soldered 0.5mm phosphor bronze wire on for pickups. This all needs tidying up, but am afraid when I get to this stage, I really need to know that my efforts have resulted in something that works. As it happens, the rods needed some easing – probably because I used Derek Munday’s heavy duty crankpins, rather than the 12BA nut and bolt that Slaters provided. As you might expect, the former are more robust, but also a tighter fit, hence the easing.

Hopefully the pictures help fill in the gaps, but am happy to say the chassis runs well – even on my old H&M Clipper. I always use this to test a new chassis. Being a simple rheostat, if there is anything sticky in chassis, it will result in jerky progress – something that modern electronic controllers often iron out to some degree. Hence you know whether the motor is likely to run hot or not too.

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Hi David,

 

I paid a visit to Downpatrick today. It was lashing rain and Railcar B is wrapped up in a tarpaulin but I stuck my phone through to get two photos... not sure if they're of any use but they show a panel with a scumbling effect and a blue surface on the floor...

 

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Thanks for thinking of me!

Am probably going to do the interior in LNER teak, which fits with the effect you mention. Trouble is we are talking 57 years on from the end of the Sligo, so who knows what fading, changes etc occurred in that time. Had the same problem with the W&M railbus. A visit to Sherringham was good for general shape, driver controls and so on, but seating fabric had not doubt been replaced a number of times and the little vehicles have been at work in preservation about four times longer than for BR.

If only Casserley, Peters and Whitehouse had visited, but don't think the famous Bentley ever got that far north, but we do at least have his fabulous film of the Tralee and Dingle. Now there's another project worth doing!

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Railcar B’s tractor unit is now taking shape. The body part is not very big [less than 2 metres long] and built around a shell of 40 thou plastikard, with 20 thou overlays to form the right tumblehome. The advantage of this is that it leaves a nice little slot to fit the glazing. Sections were also cut out for the door handles and footsteps.

The complex shape of the roof was very much made up as I went along. Began with various layers of plastic strip, then added filler and began the careful process of sanding it all to shape. This was made less easy by the headlight, which is a piece of plastic tube fronted with a spare casting from the Morris van kit. The two marker lights are two pieces of brass tube, fitted into holes drilled in the body, while the beading is 10 and 20 thou strip.

Made up a radiator unit for the roof using plastic rod and strip, with 10 thou plastic used for the box it sits in. This is let into the roof by sawing two slots. Thus far, the simple chassis seems to run well, so must hope it has enough power to pull the trailer…

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