'Peak' Decoder Installtion & Running-In

My 'Peak' now has a decoder chip fitted, in the shape of a Lenz Silver Mini (with cable harness). Whilst I appreciate the super-slow running that can be achieved with the likes of Zimo and CTE decoders, as so amply demonstrated by Nigel C and Nick M at the AGM, I find that Lenz Mini decoders serve me well. As impressive as it is for a loco to creep along at a yard every 5 minutes it's not usually something that we need to replicate on our layouts. In the real world time is money and most train operations at done as quickly as possible, even shunting operations. So all I need from a decoder are smooth stops and starts and a respectable but not super-slow speed at 'throttle notch 1'. Certainly having the majority of my fleet on one familiar decoder type helps when it comes to decoder tweaking. I do have a few examples of CTE decoders in stock and one will be going in my 04 shunter very soon, purely on size grounds.

The picture below shows the general arrangement. The decoder sits in the milled recess, tucked on top of a slip of black fag paper for insulation purposes. I'll probably replace this with PVC insulation tape before final reassembly.

In the next shot you can see the orange wire connecting to the now isolatied motor, routed via the milled slots.

Here you can see the red and black pick-up wires connected to the two halves of the chassis block. The chassis block is drilled and tapped 12BA and a couple of terminal tags made from scrap etched nickel silver.

In the final shot we see the loco with body back on, undergoing testing and running in on a Bachrus rolling road. The cosmetic bogie outer frames have been left off so the wheels and gears can be easily observed. These are great if you don't possess a circular test-track or layout but don't rely on them 100%. At first the loco ran well on the rolling road but on the track had an intermittant and very annoying 'stall' whilst running on the first three throttle notches. I eventually stripped the bogies back down again and found a few tiny rags of plastic swarf on the rear faces of the wheels near the axles, left over from the wheel turning process. These were removed with a scalpel and the bogies reassembled, also paying attention to pick-up strip adjustment. Running is now good and it runs very slowly at throttle notch 1 without a stutter now.



The only other problen I identified was that the outer pony wheels had insufficient side play on 24" radius curves, so I removed the previously installed limiting spacers. The pony wheels now actually just kiss the inside of the narrowed cosmetic side frames on 24" curves but not enough to stop them revolving or derailing.

DG's on 37

Compared to the class 45 with it's old Farish type couplings with coil springs, putting DG's onto my pair of new 37's was a doddle. They are fitted with NEM type coupling pockets which allow the N Rapido type coupling to be just pulled out.



Below we see a DG soldered onto a small brass block that is a tight fit in the NEM coupling pocket housing on the chassis underframe moulding. It is drilled and tapped 12BA and blackened. The screw is a countersunk one, also blackened.

The only modification is to drill and countersink the bogie keeper frame for the 12BA screw. The New DG coupling just drops into the pocket and nips-up tight with the screw. The coupling height comes out just right at the 4.5mm measurement above rail height that I use.

I originally purchasesd a split headcode 37 and a centre headcode one as well. Unfortunately research showed that the centre headcode ones did not arrive on NE Region until after Pool in Wharefdale closed in March 1965. Thanfully Andy Hanson was wanting a centre headcode one, so he purchased a split headcode one and graciously did a body swap with my unwanted one. Thanks Andy !

Next job is to carefully remove the existing tampo printed numbers and renumber them as Thornaby based machines. I've seen two approaches to doing this, cotton buds dampened with meths or T-Cut applied gently with a cocktail stick. I'll let you know which method worked best for me!

Chips With Everything

With 'Niddbeck Bridge' not due out again until York next Easter  I'm taking a few weeks off from layout detailing and concentrating on locomotives, namely my Farish Drewry 0-6-0' shunter and my Derby type 4 1-Co-Co-1 'Peak'.

The class 44/45/46 'Peak' was first all-new Chinese made  Farish diesel, but  is not to the latest 'DCC Ready' standard of the 37's, 57's and 42 'Warships'. This means the chassis block halves need modifying to isolate the motor, house the decoder chip and route the decoder wires. This can be done using burrs in a minidrill and hand tools but I opted to do it the quick way in my Proxxon MF-70 mini milling machine. Farish chassis blocks are soft mazak zinc alloy castings and really quick and easy to machine.

The picture below show a chassis block half after machining. The top section has been milled out to house the decoder, a wiring route has been milled along, down and then across, and the area where the motor brush tag previously contacted the casting has been machined away.

The picture below better shows the smaller square area that has been milled away to clear the motor brush contact points.

These bare machined areas have subsequently been touched up with black paint to provide a degree of electrical insulation.

In my next post I'll show you the bogie modifications I'm making before reassembling the model.