Building a DB BR V90 (BR 290)

Having already built a pair of DB's V100 Bo-Bos it seems logical to construct a model of the larger V90 locomotives using similar constructional techniques.

The V90 (later BR 290s) were intended for freight operations both in marshalling yards and as power for freight trains on the main line, especially "trip" workings between industrial premises and marshalling yards.

Models obviously need scale drawings and these shown above are taken from a long out of print book about the class.

Construction starts with adapting the former BEC tramcar bogies as power bogies (now sold by KW Trams - http://www.kwtrams.co.uk). In S Scale the V90s should have a wheelbase of 39mm so I choose to use the 40mm tramcar bogies.

The photo above shows the simple bracket that I cut and folded from a strip of brass. The bracket is held in place with bolts passed through the securing lugs at each end of the white metal frames whilst the pivot point is another bolt located above the motor securing bracket.

The two motor bogies have now been connected to form a working chassis. A length of nickel silver strip about 15mm has had holes drilled for the pivot points for the bogies. Two large washers were placed between the motor brackets and the nickel silver strip. This should give additional stability to the loco body and prevent it wobbling when the loco moves.

Using the re-scaled diagram shown above a piece of thick card was cut out to form the top of the footplate that runs around the top of the loco's frame. The shaded areas were removed as they  are the cut outs for the shunter's steps. The centre line and position of the bogie pivot bolts were marked and then......

....the card was glued underneath the nickel silver strip. By chance this gives exactly the correct height (25mm) above the rail head.

The footplate frame has now had its sides added - 5mm strips of greyboard added along each long side. This has then been strengthened with further strips of greyboard behind the outer piece.

The ends with the extension where the bonnets finish and the recesses for the shunters' steps have quite a complex shape to allow for the swing of the bogies. 

All these strips have overlapping joints to make the frame as strong and rigid as possible.

This view is the footplate frame from above/ I've marked in the position of the two bonnets and the cab as an aid to the construction of the body.

In order to make the shunters' platforms at the end of the locos strong enough I decided to make these out of brass sheet. These have quite a complex shape as they also form the upper step at the ends of the loco but also have to have a sufficient area to attach the brass to the footplate card frame. They also need to be strong enough to attach the buffer beams and the loco's couplings.

A further factor is the need to have a hole drilled through the brass and the footplate to allow the bonnets at the ends of the loco's body to be secured in place.

The shunters' platforms viewed  from above.

I've now turned my attention to the bogies. For the bogie sides I am using brass sheet cut and soldered to form an inner frame on which the detail parts will be added from card, plastic and wire.

The first stage is to cut an "L" shaped piece of thin brass and fold it as shown in the photo above. The frame will be held in place by the bolts already in place on the bogie.

The two photos above show the assembled inner frames (left photo shows looking from the bottom whilst the one on the right is from the top) . Nickel silver wires has been soldered across the ends at the bottom of the frame in order to give some rigidity.

Having printed out the bogie side frames from the diagram at the top of this page they have been glued to the brass inner frames with epoxy. The height is easily adjusted by adding an extra nut as a spacer to the bolts before tightening the fixing nut in place.

The running chassis has had its first and satisfactory run.

The buffer beams on the V90 are similar to those on the V100 so I have used the parts from the pdf kit from that model. The net shown above is cut out and folded with strips of greyboard slotted inside the buffer beam to give it rigidity.

The buffer beam is then glued to the underside of the brass shunters' platform.

Before taking construction any further I thought it best to make up a mockup of the body to see if everything would fit and that the overall impression of a V90 would be captured.

Using the coloured diagrams from the book about the V90s I cropped sections of the diagram and combined them to make a series of nets which I printed out on paper and then stuck to thin card. These were then folded into shape and the two bonnets and cab glued together to male the mock up body.

The substructure for the long bonnet has been made up out of greyboard.

The cab has now been assembled. The sides and ends were printed onto thin card and the window openings cut out, leaving the window frames in place to allow fixing of the glazing at a later stage. The thin card was then glued to 2mm grey board and the window openings cut out again. For the cab front and rear pieces the backing card was cut 2mm narrower on both edges so that the thin card will overlap the ends of the cab sides and give a neat finish. Small strengthening strips were glued inside the cab in the corners and above the windows.

To secure the cab to the chassis I've used a different technique. A hole was drilled through the nickel silver strip on the top of the chassis and also through the card of the cab floor. A 10BA nut was soldered to a sheet of thin brass which had a hole drilled through it. This was then glued to the cab floor with epoxy and a 10BA bolt passed through the hole in the chassis.

The corners on the cab have been rounded slightly by filing. The long bonnet and cab have been glued permanently together.

The short bonnet substructure has no been glued permanently in place.

To secure the bonnets to the chassis I've used the same method as in the cab. A piece of brass has been glued to the base of the bonnet and a nut for the securing bolt has been soldered in place. The bolt has been passed through a hole drilled through the main frame just behind the buffer beam.

It will be possible therefore to separate the body from the main frame by unscrewing the three bolts.

Attention has now turned to the bogies. This is a photo of an O Scale model which shows clearly what is needed

 The basic heavy metal frame is represented by pieces of 2mm thick card cut to the basic shape of the bogie side onto which other pieces will be added.

Openings have been cut where the axle boxes will be whilst 4 lightening holes have been drilled through the card.

The bogies have now been given some detail parts. The various parts have been added from a mixture of card, plastic strip, brass sheet, tube and shortened bolts. In total there are 29 parts needed for each bogie side.

The bogies have now been sprayed and