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Rebuilding the Rails Limited Dynamometer Car

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I did think I might call this topic "Pulling the Rails Limited Dynamometer Car to pieces" but that would probably be misconstrued. This topic is not meant in any way, shape or form to be a vehicle to knock the product or discuss fidelity to prototype but records my attempt to disassemble the model as supplied.


Yes I must be mad and I would suggest that people of a nervous disposition should immediately look at another topic. For those of you with stronger constitutions let battle commence.


This is a far as I have got.


First thing I did was remove the screw from the bogies:



WRONG! Start by pulling out the coupling then the bogies can be removed more easily:



You will be left with the coupling pocked and an empty space where the bogies were:



Removing the wheels is interesting as there is moulded brake gear/rods which do not allow them to be sprung out as usual so I used a small screwdriver to prise the shoe mountings away from the bogie sideframes:



A couple of the fixing pips broke off but it should superglue back without problem:



The wheelsets can then be sprung out:



Now to remove the body from the underframe/interior. A knife blade was gently levered under the body side:



A cocktail stick was slid along until I was unable to spring one of the locating tabs:


Edited by MikeTrice

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The easing/springing process was repeated until the body was free:



A knife blade was slid under the glazing:



Sliding the knife along the joint freed the glazing units:



The same technique was used for the end glazing:



The other end was also freed. Note that the two end glazing units locate the roof lighting strip:



With both ends freed the lighting bar can be lifted out with the glazing:



The side "blisters" are located by four clips as seen in this photo:



A knife was slipped under the moulding to provide some side pressure and the clips behind pushed with a finger:



The unit can then be laid aside:



The glazing of the blisters is removed the same way as the sides, slip a knife under the glazing and slide along the joint:




Edited by MikeTrice

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The side roofs are held to the body by a number of clips:



Once again a cocktail stick is wedged between the roof moulding and the body:



I found the best way to release the clips was to prise apart and release one clip at a time with my thumb:



All being well the side roofs can be lifted off (at this point I had not removed the clerestory handrails which had I done them first would have made life easier):



The knife blade was slotted behind one vestibule end:



The vestibule can then be prised off:



Repeat for the other end:


I could put I

The linkages left are a bit fragile so I pulled these off:



At this point I removed the clerestory handrails and knobs. The handrail is wire with separately moulded knobs. I found I could put the blade of a pair of tweezers behind the wire where it goes through one of the knobs then apply sideways pressure to draw the knob free:



One knob fell off and promptly fell on the carpet. By a shear stroke of luck I managed to find it.


The clips holding the underframe and interior moulding together can be unsprung:





The units could be separated and the springs carrying power to the lighting bar removed:



So far so good.


The last thing attempted was to remove the glazing in the clerestory. Again a knife was worked along as before:



Unfortunately more glue seems to have been used on these and I was unable to free the last few windows resulting in the glazing units breaking:



So a reasonably successful result and it is unlikely I will need to dismantle it further at the moment.




Edited by MikeTrice

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Why? Is it some "cut and shut" project or is there some detail Rapido left out?


Seriously though that required some nerve. Better not let Jason see this thread in case he gets some ideas about voiding a warranty lol ;)

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Why? Is it some "cut and shut" project or is there some detail Rapido left out?


Seriously though that required some nerve. Better not let Jason see this thread in case he gets some ideas about voiding a warranty lol ;)

I do intend to make some changes, just not certain which ones or how far I will go at present. Will cover these in a separate topic when I have got the nerve.

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Perhaps a Haynes Manual would be useful.......


Only useful as a pad to be put under the car jack.



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I am not sure of the changes you intend to make - I’m quite satisfied with the model as it comes, and will not be dismantling mine. I await your separate topic at a later date.

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It is about time I updated this topic. Having stripped the Dynamometer Car down to its component parts what do I intend to do with it?

Although the majority of purchasers of this model seem quite happy with it I found the model as supplied quite disappointing. I have been quite vocal in various threads about my belief that the vehicle should be lined in both 1938 and 1948. I dislike the off white roof and the more I looked at the "teak" finish the more I felt it could be improved. Examining the model highlighted a number of significant errors and I reached the conclusion that my only option was to strip it down and do a complete rebuild from the ground up.

This started as a labour of love but ended up more like the labours of Hercules and it is a great relief that I finally have a model that I am happy with. Those of you that read Tony Wright's thread will have seen some images of the finished model one of which I include here to whet the appetite:

So the time has come for me to reveal all, and show how I turned the supplied model to the one shown above.

For convenience I will break the rebuild into a number of (hopefully) logical stages covering in order:

  • Body
  • Interior
  • Roof
  • Underframe


Edited by MikeTrice
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The first step is to strip the factory finish off of the mouldings by immersing them in a bath of Isopropyl Alcohol. After leaving them for the paint to soften they were scrubbed with a toothbrush (reserved for the job I hasten to add) under running water. This process was repeated until the mouldings were clean:

Clipping the side blisters in place they do not line up as well as I would like along the lower edge. The highly visible seam is also something that I think detracts from the model:

I found that immersing the model in the Isopropyl Alcohol loosened a few more parts, a couple of which are the small windows in the end of the blisters:

To improve the fit of the blisters in the sides the top edge was filed slightly flatter:

Likewise the edges of the locating tabs were also filed in both cases with an emery board/nail file:

With these modifications the blisters now line up much better:

The plastic the model is moulded in needs a slightly stronger solvent to work and I used Deluxe Materials Plastic Magic for this. The blisters were solvented into place and the seams filled with Deluxe Materials Perfect Plastic Putty:

The Plastic Putty is unusual in that it remains water soluble after setting which makes clean up very easy. A lot of the work was done with a cotton wool bud soaked in water and drawn along the seams:

One of the strange things about the Rails model is the side duckets appear to sit on top of the side mouldings rather than being recessed. On the prototype when the duckets were fitted the mouldings were physially removed and new top mouldings produced. It may be as a result of the immersion in the IPA but the duckets now appeared slightly loose and I was able to slide a knife behind them and lever them off:

As suspected, unlike the prototype the full side mouldings were still present which might prove useful if people want to backdate the model to 1928 state. Perhaps Rapido had this in mind for the future:

Following further paint stripping the ducket can be put back in place and the fact it sits on the mouldings is apparent. There is also the additional issue that the rebate in the top mouldings is too deep:

In order to correctly rebate the ducket as per the prototype the window surrounds were pared away:

I then cut along the door opening and under the top moulding to provide a basis for removing the moulding:

The mouldings were carefully sliced away:


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I originally thought I would retain the moulding above the ducket but in the end decided to remove all of it. I lost the middle door hinge in the process:

The ducket could now be glued in its correct place and a new moulding cut in 10 thou styrene to go above it. As with the prototype the new panel is slightly shorter in height than the remaining panels:

On the blisters there is beading on the flat end which is reproduced on the supplied mouldings however presumably so the mouldings can be removed from the moulds these are not very pronounced:

My trusty Silhouette cutter cut new tiny beading as shown:

These could then be separated into the individual beading shapes:

And solvented in place. Much better:

There is a pipe run from above the vestibule doorway at the engine end that was not present in 1938 so it was carefully pared away. I have not made a very good job of it in this view but had another go at a later point in the build:

Examination of the end door at the ducket end reveals an error in the arrangement of door hinges resulting in a door that would be impossible to open:

This was pared away and new hinge added from 10 thou styrene:

At this point I was ready to start thinking about painting the body but first I had some minor masking to do. The duckets still had glazing in place which I could not remove so Tamiya masking tape was applied. I also still had two clerestory windows that were glazed so they were also masked.

The whole model was now given a coat of Halfords' Plastic Filler Primer although it is not obvious from the following photo:

This photo shows the underlying yellowish colour of the Halfords' Primer and the teak base colour having been applied with 2 thin coats using a 50/50 mix of Vallejo Bright Orange and Orange Brown:

The base colour is still slightly transparent but that does not matter as the teak graining layer will hide it:


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Now the bit I always enjoy, applying the graining using Liquin and Vandyke Brown oil paint:

A small quantity of each is squeezed out onto a palette of a white glazed tile. The tile has the benefit of being easy to clean:

The graining coat is applied and brushed into all corners and window recesses:

The brush is wiped on a tissue and than used to brush out the graining layer to match the grain direction and results in a very subtle effect:

The body is put aside for at least 24 hours and then given a couple of coats of Klear to help seal the graining. Lining using a ruling pen is now commenced:


It is one thing to physically see the lining taking place rather than me try to describe it so I took a video of the process:

Following lining the body now looks like this, ready to apply transfers:

As with my GNR 6 wheel coach the transfers for "DYNAMOMETER CAR" were produced using Inkscape:



Here the custom transfers have been appplied to the panels and shown against a prototype photograph:

The remaining transfers were applied using Fox transfers and another coat of Klear applied to seal them in before weathering. I failed to take photos of the weather process used but did produce a video:

The last stage for the body is to add a small piece of tracing paper behind the toilet window to give the crew some privacy.
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Unlike the body the interior mouldings were not stripped of paint but I did manage to pry some of the individual components off:

The floor of the Dynamometer Car is covered in lino with a very distinctive pattern. This was drawn out with Inkscape:

After printing on a self adhesive label it was carefully cut to shape:

And affixed in place:

The recording desk as supplied is a bit simplistic and I took the opportunity to super detail it. First off the crude pen groups were pared away:

New pen mounts were cut from styrene and glued in place:

The pens themselves were put together from tiny pieces of Evergreen styrene:

They were trimmed up and fixed in place. A new back bracket was bent up from brass rod and a microphone fabricated. The chair and couch in the far end were stipple painted in various colours to try and reproduce the LNER first class maquette pattern. The handwheel and measuring wheel lowering handle painted:

Wooden surrounds were also painted around the silver floor fittings and their interiors given an oil pin wash to give them form. Finally the recording table has had the log paper painted to actually cross the table under the recording pens and the end bars picked out in steel and brass paint:




I could have gone a lot further with this but decided for my sanity to stop there.

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The few colour photographs of the Dynamometer Car prior to its BR guise show the roofs to be a very dirty sooty colour.

The body was masked and the clerestory roof sprayed grey and the side roofs spray with Halfords ' Red Primer. The whole thing was then sprayed with a weathering mix:

Photographic evidence shows that the roof had a pipe (presumably gas) running along the centre of the roof between the interior lamps which had a small domed cover over the junction. These were all removed by BR and NOT reinstated when the Dynamometer Car was restored for Museum Display. Funnily enogh one of these cover was actually left in place over the toilet as can be seen in this Dave Jobling photo:

I worked out a way to replicate these covers using pieces of Evergreen 1.5mm half round strip. Bending them over into a loop and pushing the tails through a hole in a piece of brass:

Holding the brass over the sink boiling water from the kettle was poured over the styrene to start softening it:

Finally a piece of 0.4mm wire was put through the loop, the kettle applied, and the tails pulled from below to result in a domed "staple":

Having produce the roof covers I then had to work out where they should be located and at this point discovered that the roof had two torpedo vents in the wrong place. At this point I was close to throwing the whole model across the room:

Having previously painted the side roofs they were now put back into the IPA bath to strip the paint off again. The two errant torpedo vents were eased out by partly drilling through them from underneath and the resulting holes filled with styrene rod:

Note that the remaining cover on the prototype is reproduced on the model but strikes me as being a little undersized so I decide it made more sense to remove it and replace with one of mine:

Under the torpedo vents there is what looks like a washer. I cut slivers of Evergreen 1.6mm tube and solvented them into their new positions:

And t'other side:

After careful filing to thin them the holes could then be drilled through:

Here the torpedo vent has been reinstated in its new position and the toilet cap fitted. A small octogon of styrene has been applied around the toilet cover:

And given a coat of Filler Primer to check everything is OK:

Positions for the various roof covers were now marked relative to the torpedo vents and drilled then the roof fittings applied:

The central wire was chemiblacked and octagonal styrene flanges added to sit either side of the wire:

The feed to the toilet was bent up from softened wire (the wire softened by passing through a gas flame on the cooker):

The roofs could now be repainted again in normal primer and red primer:

Finally the roofs were weathered using an oil/white spirit mix airbrushed which results in just a hint of the underlying colour showing through:

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The underframe detailing looks very impressive but there are actually a lot of errors present. Below is a cross section of the underframe and it will be seen that either side of the centre line are two additional strengthening solebars to match the external ones. These are necessary as the underframe is recessed to accept the drawbar cross beam and springs:

These are not present in the model's moulding and as a result all that lovely linkage detail is not in the correct location being too high in the underframe. Note also the odd position of the dynamo which does not agree with photographic evidence:

Fortunately a lot of these errors are not visible from normal viewing angles so I was able to ignore them and just concentrate of fixing the visible ones.

The dynamo and two battery boxes are prised of with a fine screwdriver:

The small battery box has a recess on the front face that reflects the glass panel on the preserved vehicle, however this panels is only to enable viewers to see inside and was not present prior to preservation:

The recess in the small battery box has been filled, the missing strapping reapplied with styrene and grab handles fitted to both boxes:

Note the strange arrangement of the vac cylinder pistons that appear to be bent:

The cylinders were prised of with pliers after slicing through the joint with the lever:

The mounting pips for the cylinders were filed off and the hollow of the cylinders was filled with blutack and a piece of styrene rod pushed through and glued in place:

After trimming the new pistons to length the cylinders were reattached slightly further back than before:

Earlier I mentioned that the model should have inner lower solebars. At some point in the prototype history these were extended and filled in, presumably to keep some of the enclosed linkage free from dirt as can be seen in the photo of Dave Jobling's:

Two pieces of styrene were formed to represent these:

These could be glued in place on the two central beams:


A new mounting hole is drilled in the underframe and the dynamo repositioned outwards as shown:

The whole underframe is now sprayed in my dirt colour, a mix of Vallejo Flat Earth and Black Grey:


The bogies also received a coat of underframe dirt:

Replacement Hornby Disc wheels were fitted after painting in the dirt mix. Unfortunately this means that the internal lighting no longer works which to my view is not big loss.

As an aside the model as supplied has a "V" on the underframe. This tells the crew where the manual vacuum release can be found. Unfortunately the "V" on the model is incorrectly located:



















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All the major subcomponents are now complete and the various bits reassembled in the reverse order that they were dismantled. I am really pleased the way the final model has worked out and it very much rewards the effort expended. I will leave the photos to speak for themselves:























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That looks absolutely fantastic, well worth the extra time spent working on it over the original


What sort of ratio of earth to black grey do you use in your weathering mix? It looks very convincing.

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