These notes on coach construction primarily describe the scratch building of a rake of 16mm to the foot scale coaches for a previous railway.

Some additional material and photographs used to illustrate the notes are of later 20mm to the foot coaches based on Talyllyn stock, articles on these were published in Garden Rail in May and June 06 issues.  The techniques are suited to any of the larger garden scales with some adjustment to dimensions.

The intention for my railways stock has been to build stock using the same type of materials as would have been used to make prototype stock, wood for wood, metal foe metal etc. and as far as practical to adopt prototype construction.  The major concession, for simplicity and strength, has been to dispense with opening doors and use plywood in continuous strips instead of individual wooden panels.  As the coaches are painted this is not visible though when varnishing the interiors care is required to get the grain running the correct way on the panel surface.

The dimensions for the originals were arrived at after poring over a number of model catalogues, consulting details of full size coaches on a number of preserved lines and some preliminary sketches drawn full size.  The later LVR coaches were based on 7mm drawings from the Talyllyn enlarged on a photocopier to the required scale.  Having determined the overall dimensions for the originals the length was dived into three and the elevation of one compartment drawn out accurately.  From this a grid of the window openings and horizontal framing was drawn and repeated three times to produce a setting out drawing. 

 In order to ensure that the two sides were a pair and the bulkheads met the glazing bars on both sides, even if the spacing was a bit out, the grid was used upside down to produce the second side as a pair.  I do not think this was essential, my drawing was fairly accurate, but it did ensure that the duckets ended up at the same end of the brake coach! so it was probably sound practice.  When using stock drawings it also good practice to build sides as a pair rather than two off the same drawing, this is particularly the case if the drawings have been enlarged, openings often vary slightly.  I only managed to grab an odd half hour on building the sides so only doing one at once was not a problem, if in a hurry the grid could have been made wide enough to do a pair at a time. The drawing was taped to a piece of chipboard and covered with greaseproof paper to protect it. 

Two 1.5 mm ply wood strips, 53 and 8 mm wide for the top and bottom panels respectively, were pinned in place.  The framing was then built up from 6 x 1.5 and 3 x 1.5 mm hardwood strip, each piece glued in place with PVA glue.  The first pieces needed pinning but once the outside frame was in place the pieces held themselves provided that they were cut a tight fit. The strips were cut to length with a junior hacksaw and the grooves in the doorframes and top rails scored with a Stanley knife.

For the later bow sided coach a slightly different approach was required.

Rather than making the sides as a flat panel the sides were built onto the bottom panel that was already in place on the coach.  The vertical framing was pre bent by steaming and clamping with clothes pegs to an old bit of sheetmetal curved slightly more than the coach side.  Left overnight the timbers took up a shape and where then fitted and fixed to the coach side.

The floors were cut from 4mm ply and the sole bars glued in place using spacing blocks to maintain the correct distance between them.  All the ends and bulkheads were cut slightly over size and then fixed together with dots of double-sided tape for finishing thus ensuring that they were all the same. I used a disc sander with a table and 90 degree fence.  After separating the ends were fitted out with curved top rail and vertical battens, the bulkheads were left square at the top but fitted with 3mm square timber along the bottom and up the sides to window height to increase the glue surface. The sides also have 3mm square verticals at each end and strips of 5mm x 2mm along the inside at the top and bottom of the window openings.

The first attempt at assembling the originals was not altogether successful, I tried to put the whole thing together at one go.  Trying to balance all the bits using weights to keep them together was far to difficult and when the glue was dry and the weights removed there was a slight twist in the sole bars and a wave in both sides around one of the bulkheads.  Not a total disaster, a little judicious shaving and packing when fitting the axle boxes should cure the twist and running a saw part way down the bulkhead and pulling in the gap removed the bulge only leaving a slight hollow in the other side. You can just see the cut on the right of the first bulkhead of the coach on the left of the picture.

A much better solution has been to assembling the ends and sides to the floor first, putting in the bulkheads later.  The ends can be glued to the floor and held in place with pins into the ends of the sole bars until the glue has set making a secure unit onto which the sides can be glued and held with the same weights, see rear coach in the photo.  The sides can be sprung with a strut to enable the bulkheads to be dropped in and held with pins after removing the strut. The corner battens on the ends and the buffer beams were added after the bulkheads held with pins and clothes pegs respectively, right hand brake coach in the photo.

The opening sashes for the doors were cut from card and glued to the inside of the door uprights, I was not into mortise and tenon joints in 1mm timber!  Hinges were cut from cocktail sticks and glued into the groove on the hanging side of the door, having checked right or left hand hanging on each side of the coach.  For the roofs five ribs were cut in 4mm ply to match the roof camber, tacked together with double sided tape, sanded to profile and notched out to take a pair of longitudinal stringers.  A simple jig made with nails in a piece of chipboard held the ribs and the stringers while gluing together.  Second mistake, I tried to clad the frame with sheet balsa but it was just not strong enough, fortunately the frame was more substantial and after stripping of the balsa attempt two was tried, two sheets of 1mm ply laminated together onto the frame, success, easy to do and very, very strong.  The frame was fitted into the coach after laying a piece of cling film across it and resting on a pair of pins at either end to raise it above the coach sides, this ensured that it would fit after gluing but did not stick it to the coach.  The timber covering was weighted in place with a pair of car mats and a couple of pieces of hardwood.

More recent practice, right hand picture, is to board roofs with ply or timber strips made into a sheet by edge gluing.  The board joints show through the covering just like the real thing.

The first photo also shows the underside of a completed roof, already primed with acrylic primmer, the two notches visible on the first rib indicate which end of which coach it belongs to, no they are not all identical!  The top of a third roof shows the strips of card glued on to represent cover strips over the joints in the canvas covering.  Current roofs are fitted with lighting, see below.   At this stage everything was rubbed down with fine wet and dry paper used dry.  The interiors were painted with silk emulsion paint above the windows and light wood stain below. The floors were coated with a darker stain to look like a lino covering.  The outside was primed with two coats of water based white acrylic undercoat slightly thinned to give an even base colour.  The underside and ends then received a coat of blackboard paint over coated with eggshell varnish. The sides were painted with Humbrol matt paint, the green took three coats.  The red lines were cut from a 12mm car stripe and stuck on.  Recent attempts at lining with a John Mores pen have proved superior for fine lining work. Third big mistake was to apply transfers onto the side of a coach before varnishing with Humbrol gloss varnish.  The green changed colour with the varnish but not where it was under the transfer.  Rubbed of the transfers, touched up the green and re varnished before applying the transfers, then a second coat over the transfers.  The roofs were treated to a coat of the same white primmer, unthinned, and with sand mixed in before painting with grey undercoat and matt varnish.  The finish is a bit course but I was getting a bit short on patience at this stage.  Subsequent efforts use a fine cotton cloth to represent canvas covering, the roof being coated with PVA glue, the cloth placed on top and the glue worked through with a strip of plastic.  All this may read a bit longwinded but it took longer to accomplish than everything that preceded it!

In between the coats of paint the various bits required to finish the coaches were made up.  Having been associated with the motor industry for a number of years I appreciate the value of jigs and fixtures if you want to make and fit a number of components that are the same.  When it came to making and fixing the ironmongery jigs were the order of the day.

A

Cutting jig for cocktail stick hinges, the block is drilled to take the stick and a Stanley knife used in the slot with a rolling action. take out the nail stop and push out the 'hinge'.

B

Rectangular tube with slot to bend step brackets, top drilled to take 2mm bolt & bottom 1mm to take brass track pin through step and bracket then riveted. Bracket fixed to the step in the background.

C

Square tube section with radius corners to bend handles.  Legs left overlong and trimmed before fitting.

D

Brass plate drilled to suit position of grab handle and door handle on door stiles, bent at a right angle at the bottom end and pushed tight against the bottom of the side panel, held in place with Bulldog clip top and bottom while drilling..

E

A prototype handle, not made on the jig the radii top and bottom are different!  The washers were soldered on in a wooden jig and then filed on the vertical edges to make a rectangular plate with radius top and bottom edges.

F

Buffer height jig, will be used for all stock. The base was made from two pieces of ply the lower fitting between the rails the upper sitting on top.  The base sits on the rail and the coach is pushed against the sharpened bolt marking the height on the buffer beam.  (Check the centring across the coach by measuring, play in the axles  and overhang can make quite a difference.)

At last the fun bit, sticking on all the fancy bits.  Holes drilled in the sides using the jig and the door handles and grab handles glued in using clear Araldite Rapid.  A bit like mustard, you waste more than you use as it goes off pretty fast.  The second big mistake was trying to glue and screw the axle boxes onto the sole bars. Despite drilling pilot holes and screwing on dry first it proved impossible to fix them accurately when glued. Plan B, glue the boxes and wedge in place with two short bits of wood across the coach, check they are square then sit onto a surface plate and if necessary tweak with a screwdriver between the spring and the sole bar until all four wheels sit on the plate. Leave to dry, then drill and screw, easy when you know how.  (I use a piece of laminated glass as a surface plate, satisfactory for this sort of work but don't be tempted to hammer on it!)  The steps were bolted through the floor with 2mm bolts.  The windows went in easier than expected, two strips of acetate sheet cut to width and joined on one of the centre door posts, threaded in from the middle compartment.  The roofs can be made quite a good fit using the method above and are left unsecured for access to the interior.

Current stock has lighting in the roof running from its own battery pack under the floor or the seats.  Lampshades are made from the tops of sport drink bottles some resemble cut glass domes.  Contacts from old relays fitted into the ends of the roof connect with a brass plate on the inside of the coach end to supply the power, they also help to secure the roof.

 On the whole I was quite please with the end result 

The paint finish was not as good as I would have liked but better than I expected.  Painting with mat paint and then varnishing allows for touching up individual panels or frames, the varnish coat blends everything afterwards, not so with gloss paint. The coaches are individual and the originals did not cost a fortune, about £12 each, but I did have most of the timber lying about. 

More recent efforts have cost even less as I now make my own axle boxes.

Experience gained on the original rake has enabled improvements to be made on the later coaches for the new railway.  Techniques have been improved and some new ones discovered.  An enforced period without workshop facilities and the discovery of Plasticard for working on the dinning room table was one.  Whilst this has involved some compromises to the original intention of using prototype materials it did allow construction of stock to continue.  Plasticard has in the event proved invaluable in simplifying the manufacture of none structural parts that would have been time consuming and may have require commercial castings.  As another of the criteria was to scratch build as much of the new railway as possible at least that intention was not compromised.

Bill Winter  04 revised Feb 09