Prickley Pear GNSR First (Sort Of) and Friends

Armchair Modeller
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Prickley Pear GNSR First (Sort Of) and Friends

Postby Armchair Modeller » Thu Sep 22, 2016 10:12 pm

Invigorated by my success in soldering up a London Road Models 42ft turntable, I got another brass kit out of the gloat box to try out. I bought a Prickley Pear GNSR Dia A1 1854 First kit 2 years ago at Scaleforum. These were built by Brown Marshall who may possibly have designed them (speculation), so I assume they could also have been built for other railways. Originally, I planned to have First Class accommodation on my tramway, but punters turned their noses up at such vintage transportation - even more so once the Motor Age dawned. So, it's being modified slightly and relegated to departmental service stock. I always worry what kit manufacturers think of idiots like me who throw all their painstaking research and accuracy in the bin, all in the interest of originality - but here goes anyway. ;)

So far, the underframe has been built, more or less as Prickley Pear intended. The only big difference is with the suspension. I prefer a sprung chassis if possible for my P4 rolling stock. This one is deliberately designed by Prickley Pear for a 3-point suspension using a rocking axle at one end. I hate this form of compensation, mainly through experience in 2mm finescale a long time ago. The whole principle seems unstable - and only forced into submission by a huge amount of weight. Reasons are conveniently covered in Julian Roberts' loco suspension article in the latest Scalefour News. My theory is that a 3-point suspension will be far more satisfactory if both wheels on one side of a 4-wheeled vehicle are compensated instead. I am sure someone must have thought of it long before me. Leonardo Da Vinci probably did a sketch of it sometime, somewhere, for example. What I did is best explained using photos.

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This one shows the rocking side of the underframe. I used a short rod bent at right angles at both ends after inserting in a brass tube to make the pivot. The compensation beam is soldered to this rod. I soldered a small piece of oversize brass tube on the corner of both W-irons after cutting a small part of the W iron frame away to allow the compensation beam to be inserted. All the rod I used for this side of the chassis is 1mm brass.

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On the other side (above), I used smaller 0.7mm diameter brass rods in brass tube. Each rod is soldered to the outside of one of the W-irons. It is held in place by a small length of brass tube at each end, soldered to the underframe. These tubes act as hinges and also keep the w-iron in position both laterally and longitudinally.

I then inserted wheels and tested the underframe on my infamous track. Even without any extra weight, it worked perfectly - even on the deliberately deadly loco siding (phew!)

Since then, I have added the lower footboards. Should have read the instructions really, before I did the suspension, as the tubes on the fixed wheel side blocked the holes for the footboard bracket fixing points. Fortunately, I was just able to drill small diameter holes through the side of the tubes next to the solebars without interfering with the suspension. As a precautionary measure, I widened the gaps in the footboards around the axleboxes a little bit, just to make sure I have good clearance. Here are a couple of photos with the lower footboards in place.

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Overall I am really pleased with how this kit has gone together so far - and with the compensation system. It involves just a little more work than a rocking w-iron but seems far more stable, even with minimal weight to keep the wheels down on the rails. This solution worked well for this particular chassis. For others I might well have to modify the design to some extent.

Next, I will assemble and modify the body. Not a session for the purists and rivet counters, I am afraid. Just another little bit of fun. You have been warned ;)
Last edited by Armchair Modeller on Tue Oct 11, 2016 12:10 pm, edited 4 times in total.

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Re: Prickley Pear GNSR First (Sort Of)

Postby andrewnummelin » Fri Sep 23, 2016 9:41 am

Armchair Modeller wrote:... My theory is that a 3-point suspension will be far more satisfactory if both wheels on one side of a 4-wheeled vehicle are compensated instead. I am sure someone must have thought of it long before me.

This brings back happy memories from more decades ago than I care to count - when still in school I joined the Wimbledon MRC and first saw the smooth running of wagons built with this concept, but I regret I cannot remember who built the models. Being long before the days that etched components were commonplace, the system employed had the whole solebar rocking, the gap between the floor and solebar was visible if one crouched down, but viewed from normal (for those days) heights the gap was hidden by the wagon bottom rail.
Does anyone know who the modeller might have been?

Keep up the good work!

Andrew Nummelin

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Re: Prickley Pear GNSR First (Sort Of)

Postby allanferguson » Fri Sep 23, 2016 10:37 am

Looking at my records I find it was 1991 when I built this Scottish Central Railway birdcage brake. For some reason I was unhappy with the rocking W iron, and chose to fit a pivoted dummy inner solebar, which has the lower footsteps attached to it, as well as pinpoint bearings. It was secured to the real solebar, and pivoted on, a 12BA screw soldered amidships to the inside of the real solebar. It was invisible in use, and worked well, though I'd be reluctant to be dogmatic about it, as it's sat in a cupboard for 25 years.

Allan F

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Re: Prickley Pear GNSR First (Sort Of)

Postby Armchair Modeller » Fri Sep 23, 2016 11:08 am

There may yet be room for a patent application then, as neither idea is quite the same as mine ;)

Seriously, good to hear that others have tried similar ideas and find that it works!

Thanks for the encouragement Andrew! :thumb

Looks a really interesting model, Allan. Shame it is kept hidden away! :o

Armchair Modeller
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Re: Prickley Pear GNSR First (Sort Of)

Postby Armchair Modeller » Sun Sep 25, 2016 10:29 pm

A visit to Scaleforum resulted in the purchase of a GNSR Brake kit to go with the First Class coach, so I suppose you could say that I now have a Prickley PAIR. (sorry!)

Second thoughts on the role of the First Class coach mean that it will now be part of a passenger train after all. Non-revenue stock is a bit of a luxury until I have several passenger trains to run - and I am still researching the double deck tramway trailers, so building those may yet be a while off.

The First Class carriage will now form part of a conductor guard-style train with compartment partitions opened up and a door in one end to allow the guard to move easily between vehicles. Similar adaptations were made by some real railways. This kit already comes with a spare door. I cut a gap out of the non-step end of the carriage with a sharp Stanley-style knife. The door was then soldered onto the inside of the end. It will represent and inwards-opening door. There is still a bit of detailing and filling to do, but this photo shows the basic idea.

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I have also fitted all door ventilators and droplights. A few extras not included in the kit were bought at Scaleforum, including torpedo ventilators and some brake components. I will add these as I progress through the build.

The Brake Vans were built by Joseph Wright & Co in 1860-61, so just like the Brown Marshall First Class carriages, they could easily have been built for other railways too.

Armchair Modeller
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Re: Prickley Pear GNSR First (Sort Of)

Postby Armchair Modeller » Tue Sep 27, 2016 8:32 pm

Well, the body is almost complete, despite some very fiddly bits. In the end, I more or less followed the kit instructions to produce a fairly standard coach. The most noticeable difference from the kit is the extra door in one end, which I explained last time. I have also put long handrails next to the doors, in preference to the ornate, but small grab handles provided in the kit. I made the extra handrails out of spare wire from the kit. Some of the roof detail is still missing, like lighting and ventilators which I will add at a later stage. Underframe details like brake gear and a battery or gas cylinder for the lighting will be required too (not supplied with the kit, for obvious reasons). Here are a couple of photos showing the body, roof and chassis loosely assembled for the photo shoot.

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I will probably permanently fix the roof to the body and screw the body to the chassis. This is provided for in the kit, though Mt Prickley Pear recommends soldering the body to the chassis in the instructions.

This is my first ever etched brass carriage kit, so I am really pleased with how it went together. There is a small amount of cleaning up to do, but nothing like as much as I expected, given all the tiny details that had to be soldered on. I still have to craft an interior and add the castings.... and then there is the painting. I haven't even worked out yet what my tramway's livery will be.

All of this can wait until I have got thus far with the other two vehicles in this rake, the Prickley Pear GNSR Full Brake and an LCDR 3rd which I bought recently from Roxey. The three should make a really characterful mixed set. In the meantime, I hope to get the trackwork finished and fully operational on the first baseboard.

The roof looks grey in the photos for some strange reason - it really is just brass at the moment.

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