Fiddle Yard Cassettes for Trinity Dock Street Bridge

Gavin Rose updates us on the latest developments at Trinity Dock Street Bridge

Trinity Dock Street Bridge is a 4mm scale / OO gauge layout set on the old town docks in Hull, Yorkshire, just pre WWII.

The layout had to be reasonably small as space was minimal and the whole layout is only 2000mm (7 feet) x 600mm (2 feet) in the main, with a 550mm (1’10”) x 475mm (1’7”) extension to the rear, making for an unequal ‘t’ shaped layout.

There is a fiddle yard to each end, these being 400mm (1’3”) long leaving 1200mm (4 feet) in the middle for the ‘scenic section’.  These short fiddle yards threw up a big challenge as to how to make it work.

Initial attempt was to use a hand operated and much modified scrapped Hornby turntable in each yard as a wagon rake selector, with the wagons being stored on several radiating storage tracks.  This worked well at home but I found that the time it took to change loco’s (by hand lifting) select another rake of wagon on the turntable and re-couple (3-links) and send the train off to the other end was rather long and spectators at shows would drift away.

So, I had to adopt a quicker way of changing the trains on the model, and therefore keeping interest up longer.  The decision was made (with a fortnight until the next show) to make a cassette system, similar to one I had noticed on a layout at a show I had seen in Stoke in 2017.

Several ideas were bounced around my head, such as PECO track stuck in the bottom of a cut down gutter section, but kept coming back to the idea of the cassette made from aluminium angle and plywood base.

Went on t’interweb and found a supplier of ali angle (‘Metals4u’ https://www.metals4u.co.uk/aluminium/c1/angle/c12/25.4mmx19mmx3.2mm-(1x34x18)/p8697) these supplied the angle, in my case 25.4mm (1”) x 19mm (3/4”) x 3.2mm (1/8”) cut to length (+/- 0.25mm), mine were cut to 375mm in a mill (raw) finish, with a turnaround of 3 to 4 days I soon had my mits on them.

First thing to do was clean up the edges and round off corners as these were quite sharp, along with any lumps on the running edges where the stock would run.  Once cleaned 3.5mm holes were drill 10mm from each end and in the middle of the widest leg (25mm) of the angle, at 10mm in from the running edge.  These were countersunk in the upper side and de-burred on the under, then set aside.

The bases were initially made from 9mm MDF, but this was changed to 5mm exterior plywood as it fouled the baseboard in the fiddle yards.  The ply was cut 20mm shorter than the angle, the reason will come clear later. The bases were cut to 59mm, this allowed the cassettes to slot together for storage (albeit this hasn’t worked as well as I wanted).

With the use of a carpenter’s square and a straight ‘tracksetta’ pattern the angles were screwed to the bases, with 10mm over hang at each end of the angle and equal 3mm approx rebates to the long sides.  I used 3mm x 10mm wood screws as this gave me a little bit of play to adjust as needed later.  Any screw poking out the bottom was then filled off to avoid snagging on things like fingers, etc.

The wood was painted black, purely for aesthetics to match the rest of the fiddle yards and any over paint on the aluminium rubbed off with wire wool and a track rubber.

The cassettes now complete, the issue of getting them to stay in position was dealt with with more Aluminium angle (from the same supplier), this time 25mm lengths of 25.4 (1”) equal angle, drilled, countersunk and screwed on to the baseboard using the cassette as a guide.

At the ‘running on’ end the two pieces of angle is suspended off a piece of copper clad sleeper glued to the top of the raised section of the fiddle yard (the top of which is about 12mm (1/2”) below the top of the rails on the layout, so the run on lines are on a piece of 9mm MDF).  I have glued some foam rubber between the locating angles at the ‘dead-end’ of the yard, this helps to remove any unevenness in the cassette/baseboard and also make the ‘running end’ edges contact the copper clad better as the rubber forces the live end on to the contacts.

Electrical continuity is via a common and a switched feed (via household light switches, they are robust, large and easy to locate when you are talking to the punters) to not only the run-on tracks and copper clad, but via bussbars to the locating angles too, so contact through those too, sort of a belt and braces approach.

While not in use the spare cassette, be they full or empty, sit on top of pieces of 12.5 (1/2”) equal ali angle, drilled, countersunk and again screwed to the baseboard, these are not powered, but do allow for the cassettes to be slid toward the running tracks before they are needed, when they are lifted in place.

Now, change a train takes about 15 second as opposed to a couple of minutes as it was before!  Certainly a great improvement even after only one show.  The will be even more efficient now I have the third fiddle yard to the rear of the model where trains run off the model via a lifting door in the back scene!

Are the cassettes finished, no, I need to make some sort of safety gate to each end to avoid trains sliding off the cassettes while they are being moved between yards, a risky task at the moment.

Fiddle Yard Cassettes for Trinity Dock Street Bridge

Should you have any queries, please get in touch.  Oh! The layout has it’s own Facebook page,  @https://www.facebook.com/trinitydockstreetbridge/  if you want to see more photos of the fiddle yards or the layout as a whole!