Author Topic: Got a "wiggly" GRS GWR Auto coach trailer?  (Read 221 times)

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Offline John Candy

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Got a "wiggly" GRS GWR Auto coach trailer?
« on: October 20, 2017, 09:19:32 AM »
Got a "wiggly" GRS GWR Auto coach trailer?

In the course of refurbishing one of these coaches for a friend, one of the issues (seems common to these rather flimsy sided resin coaches) was the "wiggly" sides, which result from a lack of support at cant rail level.

Don't put up with this, there is a quick and easy solution. Remove the roof, cut small recesses in the edges of the transverse partitions just deep and wide enough to insert lengths of square brass (I used 3/32 in. square brass tube, simply because I had some spare). I used a razor saw and snapped off the recesses with small piers. Then position brass flush with the top of the car sides and a small blob of "5 Minute" epoxy at each end will fix the brass to the partitions. You will find that this alone will have made a vast improvement but I went further and added transverse brass components half-way along the side strengtheners, to protect against flexing when handling the coach.

Finally, I fixed (with epoxy)the resin sides to the glazing and glazing to the brass with a thin film of epoxy, being careful not to get glue on the glazing, and used small spring clips to hold the resin/Perspex/brass sandwich together while it cured.

 John.

Click on photos to see full view.











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Offline John Candy

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Put the "Spring" back into your Autocoach buffers.
« Reply #1 on: October 30, 2017, 07:21:56 PM »
Put the "Spring" back into your Autocoach buffers.

The extensive refurbishment of this GRS autocoach required some serious attention to the buffers.  A couple were very stiff, another had lost all springing and the fourth was jammed solid into its housing.
Dismantling soon disclosed the reason.....poor design.

The cast brass buffer heads had shafts which were rough and heavily oxidised, while the coil compression springs were wrapped tightly around them and forced into a tightly fitting "tunnel" which formed the guides.
There was little chance of effecting a permanent solution by rebuilding using the same methods, so a more drastic method was used, involving external springing.

See the photos but the basic method was to cut four lengths of 5/16 inch (thin wall) brass tube each 20 mm long, then blank off one end with a square of sheet nickel silver (brass would do equally well) attached using a 221 degree solder. Next some shortish lengths (about one inch) of 5mm x 0.75mm brass strip were shaped at one end to follow the curvature of the tube and then soldered (see photos) using 145 degree solder.
Next insert a compression spring in the tube : I selected four springs, listed as 5.6mm x 17.5mm, from a box of "Rolson" assorted springs, bought for a couple of Pounds.

The next stage is "trial and error" but quick and easy....it took just 10 minutes to all four units.

First bend the attachment strip so that the unit can be aligned with the tail of the buffer shaft. When in the correct position, the nut on the shaft will engage with the spring and the buffer will compress and extend smoothly. Now "fine tune" the shape of brass bracket and drill two holes (one to accept a small self-tapper, the other a 1/32 in brass rivet).  Re-locate the unit, test again for smooth operation and then screw to the floor. If there is a tendency to rotate, then a rivet can be used through the second hole but a drop of thick Cyano glue will normally be sufficient to prevent rotation.

Squirt some oil into the housing and you should have no further problems with the buffers.








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