Dapol Class 73s…into traffic!

March 28, 2017

No. 73 108 in late condition, photographed at Eastleigh in 2002.
Faded, dirty but still doing its stuff on the SE TPO.

No. 73 108 is one of the locomotives I have chosen to model using one of the two new Dapol models to recently arrive on Folkestone East. Conversion to EM turned out to be the simple, involving the regauging of the split axle wheel sets which have a good profile on them – good enough to run smoothly through my hand built track.

There are many well-thought out technical features of this model. The body lifts straight off after releasing the retaining screws – no pesky clips to fight. Don’t loose the screws though or you will be scr*wed when it comes to putting the body back. There is a good space for both decoder (nearest) and a sound speaker. A 21-pin socket ensures all lighting features have power.

The circuit board makes contact with circuits in the body by means of a row of sprung contact pins which eliminates linking wires and plug and sockets. However, I did not want the cab lights illuminated and was looking to fit a decoder with ‘stay-alive’ (‘keep-alive’) . The only one I had to hand was a wired LaisDCC one which works well with this mechanism. 21-pin versions with stay-alive are also available. I also wished to work the head code lights independently using red LEDs, so decided to remove the circuit board and hard wire a LaisDCC decoder in place with its stay-alive capacitor. The lighting connections to the circuit board are easy to locate and desolder, so this hard wire DCC conversion is easily reversed – the circuit board being stored away safely.

The image above shows the hard wire installation, with the head light LEDs wired with 5k Ohm resistors to reduce the fierce light to something a little more realistic. Connections will be made with the head code box LEDs too.

A stay-alive unit is seen in this image. It was not quite powerful enough to power the Dapol Class 73 when it lost contact through those pick-up bearing rings. In the end, I built a new stay-alive unit with some higher Farad rated capacitors with great success. The higher rated unit was still connected to the same LaisDCC decoder. It is worth mentioning that even the smallest capacity stay alive unit will prevent light flicker in the most reliable models even if there’s not enough juice to deal with a serious stall. In many instances, the flywheels fitted to modern mechanisms will carry a loco over a minute dirty spot without interruption,. The only hint of a problem will be a flickering of LED head and tail lights. Stay alive units also smooth the operation of locomotives that otherwise seem to run well.

A final look at the DCC installation. It may seem strange to remove the convenient 21-pin DCC interface. However, wired decoders offer so much more flexibility in terms of organising lighting effects and this installation turned out to be quick and effective. The model is numbered 73 108 with an address of 3108 and is now hauling trains on Folkestone East. It is at this point I must admit to keeping two Lima EDs, stripped of drives and in the process of being reworked with Dapol detailing parts. One is No. 73 129 ‘City of Winchester’ which is used as a trailing unit in the SE TPO so the train can be top and tailed. Two Dapol EDs on this train is overkill. The second loco was also a regular on the SE TPO: No. 73 131 which will eventually be refinished in EWS livery.