Birth of a railcar

the prototype railcar delivered in 1934

It might seem a bit potty writing about how I developed a railcar for County Gate, but the exercise might serve to help those building freelance designs to achieve results that may be more realistic and credible.

Thanks to the internet, we are now blessed with an almost infinite information resource and there can be little excuse for historical inaccuracy. I spent three times as long developing the design as I did building it. For me, I must say, this is the best bit.

I worked to the following criteria:

1.   Railways were a business, so there has to be a jolly good reason for the company to spend any money.

2.   The resulting equipment must be 'fit for purpose'.....(I have always wanted to use that expression!)

3.   The equipment has to reflect technology of its time taking into account the budget available.

4.   The aesthetic design should reflect the trends of the time.

Unlike less fortunate narrow gauge lines such as the Festiniog, the Minehead and Barnstaple enjoyed financial backing that saved it from improvisation.

operating criteria were as follows:

1.   Low operating costs with minimum staff requirement and training.

2.   Driver control from each end.

3.   Instant deployment and let down.

4.   Good acceleration.

5.   Comfortable, silent with good views of the landscape.

6.   Well lit and heated.

7.   Minimum damage and wear to trackwork: no hammer blow and low axle ratings.

8.   Reflect the 'modern image' of the Southern Railway.

Huge advances had been made in railcar design in France and by 1931, the Bugatti factory was producing main line high speed railcars for their Paris to Lyon service. One of these units is preserved at the National Railway Museum at Mulhouse.

These advances also trickled down to the metre gauge lines throughout France with considerable success.

Billard Autorail on the Corsican Railway

the motor bogie of a Billard

There was a surge in 'modernism' which had also begun to grip management at Eastleigh. It was therefore decided that the new railcar would incorporate all the latest practices and reflect the modern image. Great Britain had been somewhat slow to embrace the diesel engine, in part due to the ongoing dislike of anything German. The British Company, Gardner, had begun to produce an excellent range of diesel engines in the lower power ratings but it was not until after WW2 that the more powerful 8 cylinder engines came into production.

Transmission was given some serious consideration. A number of railcars had been built in Ireland, using buses as the donor. These units had mechanical gearboxes and were provided with only one reverse gear. This meant that the units had to be turned at each end of the line. Such an arrangement was unacceptable for Eastleigh, so hydraulic and electric traction were investigated. Considerable experience had been gained with electric traction for many years with tram systems. With power on board, lighting and heating could also be easily arranged. In addition, diesel/electric traction meant that the engine operated at a fixed r.p.m.  which was far easier to operate with remote driving positions and engine life would be significantly increased.

The Swiss company of Sulzer was therefore chosen to supply the power units.

Running gear would be all bogie, which would reduce track damage, minimise axle loadings, permit greater speed and offer the best comfort. By placing the tractor unit at the centre of the consist in a separate car, noise and vibration could be minimised. A narrow corridor would be provided for passage of the guard and bellows corridors fitted to each passenger car. The engine compartment was separated by a soundproofed partition. A large electrically operated fan was installed at roof height to draw air through the radiator.

click to enlarge

The bogie design was advanced for the time, with the provision of the newly developed Armstrong lever hydraulic dampers to control roll. Braking used the Westinghouse system with air provided by an electric powered compressor.

These were constructed using the Voisin semi-monocoque system that had been developed in the 1920s. Door and window pillars were cast aluminium, flush riveted to a light steel frame panelled by aluminium panels. The assembly was mounted on a ladder frame. The windows were laminated glass and did not open. Ventilation was provided using a forced air system and heating and lighting were electric. Comfortable seating was provided in art deco style. An offset corridor gave access to seating and ingress was effected by air operated sliding doors.  The newly invented Kent Clearview units were fitted at the drivers stations to clear rain. These consisted of a spinning disc of glass which threw out rain droplets. The drivers stations were provided with remote engine instruments, brake and pressure gauge and a 'dead man's throttle'. A master key was utilised to immobilise the unused station. The engine could be started from either end.

Loading gauge restrictions maintained the overall dimensions similar to the existing coaches on the line.

The design would be flush riveted throughout. The nose section was worked on several times before the final design emerged.

During the 1930s, aerodynamics had become better understood by the public. If the railcar was to be successful, it would have to significantly reduce journey time compared to buses and private cars. (This concept is correct. The metre gauge line Nice/Digne is still operating to this day for local traffic due to the bad roads.)

The final design was much further raked which was felt would depict speed best on advertising posters. The front however was flat to reduce construction costs and the window height raised to improve views of the countryside..

The railcar was completed in three long days over a wet holiday weekend. A Graham Farish long wheelbase bo-bo chassis was purchased new from Hereford Model Shop. This effectively set the length of the tractor unit.

The plastic outside bogie frames were removed and the coupling boxes sawed off. The sides were then painted and weathered prior to refitting. The foundations of this articulated railcar are the corridor bellow connections. These will be later epoxy glued to the chassis, (BUT NOT YET). They should be a tight fit onto the chassis body and should be made really square as the passenger cars will be supported on them. Thin square section Plasti-strut is glued to the outside to represent the bellows. Once dry, the grooves were 'distressed' with a cut-off disc using a Dremel. Once the part looks like a corridor connection, it is quickly coated with Plastic-weld to melt off any fur. The bellows were then painted and weathered and left to dry.

It is now time to make the car sides. Unless you wish to get into resin casting, they will be made in 1mm Plasticard. I always lightly sand one surface to remove the gloss. It makes marking out much easier. The window apertures are carefully marked and the corners drilled with a .5mm drill. This makes removal of the blanks far easier. Remember that accuracy here will make or break the resulting model. The blanks are then carefully scribed with a very sharp craft knife and then 'popped' out. Great care is needed not to distort the narrow window pillars during this process. The apertures are then cleaned out very carefully with the knife, making sure that the cuts are square. The window  and door apertures are then filed into a rounded profile.

You will need to prepare 4 passenger car sides, (2 mirror images), 2 ends and the sides of the tractor car.

I do not intend to present scale drawings for this model. The exact design and sizes are up to you!

Once the work is done, it is time to make the curved roofs. Select 3mm square Plasti-strut (or laminate thinner sections together) and glue flush to the tops of the car sides and to the sides of the front panels. The unit can then be assembled.

Next to make and install are the floors. These are in 1.5mm Plasticard and are recessed into the body to accommodate the bogies. We purchased two good quality N gauge coach bogies. These are mounted on Plasticard bolsters glued to the floor. On our model, clearance below the coach side was set at 3mm. Remember that the floor does not extend right to the back as the drive bogie has to be accommodated. Once the complete assembly has thoroughly hardened up, the really boring bit starts.....sanding the curves of the roof. For removing most of the material, I used 100 grit production paper glued to a really flat surface. Take great car as it is much harder to put material back! I finished off with 180 freecut paper. Any slight gaps in mitring can be filled with car bodyfiller.

Now is the time to cut and fit the inner window frames. These are 0.5mm smaller than the apertures. Despite best effort, there will almost certainly be some variation in window size. Just offer up a thin piece to Plasticard and mark around the hole with a 0.5mm Rapidograph. Remember to pre-sand the surface so that the ink takes. The inner frames are then carefully glued in. The rear sliding door should be made of 1mm plastic.

It is then time to add detail. Bogie inspection hatches can be scribed in and hinges made in very thin Plasti-strut.

A hole is then drilled dead central at the rear of the support plate to take a small screw. This will act as the articulation pivot. The nut of the screw is fitted into a corridor bellows. I fitted the nut 5mm in, so that even when the cars were around a sharp corner, the end of the bellows cannot be seen. Firstly drill through the bellows with a clearance hole for the screw. Then attach nut to screw and whilst heating with a soldering iron, slowly push the nut into the bellows so that it is flush. Make sure that the screw remains upright.

Screw coach units to bellows.

The build is very similar to the coach units except that no floor is fitted. It will be attached to the bellows once these are glued onto the Farish chassis.

Once the square section plastic has been glued to the roof, fill with car body filler and sand flush. Sand the curves into the plastic extrusion as before. Drill two clearance holes 3 mm from each end of the car dead central. Then drill to partial depth a larger hole to lose the head of the screw.

Place the motor chassis on a sheet of glass and slide on the bellows at each end with the passenger cars attached.  Drop on the tractor car body and ensure that there is sufficient clearance between the units to allow for the track curvature required. Apply 5 minute epoxy to the inside of the bellows and attach to the Farish chassis. The height of the bellows can be adjusted at this time to ensure that the passenger cars are absolutely level. Once satisfied and the glue has hardened, offer up the tractor body and pilot drill through to the bellows. Again, nuts can then be melted into the plastic of the bellows.

the tractor unit of the prototype

This is up to you. We fitted lights made out of plastic tube. This were filled with epoxy to near the surface and reflectors painted on. Once dry, a drop of epoxy hardened to become very convincing lenses. We made louvres from Plasticard and installed the exhaust system. We also added fuel filler and water cap. We also added a strip along the length of the units as a waist.

Once satisfied, dismantle the model and spray the required colour. We use a plastic etch paint first, supplied by Currys. The interior of the passenger cars is then hand painted to the required colour. Transparent plastic is then fitted to the windows. We use 'Clearfix' for this. Add seats and passengers and then attach the roof, cut from thin plastic sheet. Mask off the model, and spray the roof.

We ballasted the passenger cars with lead shot glued to the underside. Add door handles, couplers if you wish but buffers for a minimum, etc...and I guess you are about there. Enjoy breaking new ground in railcar design and don't forget, that many young people can relate to such machines much easier than steam engines.

The model runs better than anything else we have on the line and the articulation looks wonderful round the curves. We built ours for a minimum radius of 12".

At the end of 2010, this railcar was withdrawn from service as there are sufficient trains now to use all the available slots including spares.