Introduction

In 2013, the Club published several of my papers relating to problems that arose with my DDE model. These can be found under the Loco Repairs section: https://www.oolivesteam.com/dp-loco-repairs

After about 12-18 months’ storage since their previous runs, I recently tried to operate all three of my LS models. All three were sluggish. Flying Scotsman improved quickly after fresh lubrication, pulling well and with a good range of controllable speed.

Silver Link Issues

SL was lubricated with Hornby steam oil before test running on the rolling road. She was very reluctant to run evenly and misbehaved badly on the track. After cooling, she was stripped down for cleaning with isoprpropyl alcohol (IPA), followed up by aerosol printed circuit board cleaner. During cleaning, it was evident that the tender pickups were worn out, so these were replaced with new ones sourced from the Hornby Live Steam Club. Axle bearings on the loco were lubricated with Labelle #102 gear oil. Gearbox and other steam-related mechanisms were lubricated with Hornby steam oil. Tender wheel bearings were lubricated with Peco Electrolube.

SL now runs freely and pulls well.

Dwight D Eisenhower issues

DDE exhibited several faults. She did run for a short while, but then stopped completely with a full boiler. The reversing mechanism, which had been operating more than it should due to poor track voltage, stopped completely and the servo motor stopped altogether.

After removing the body for inspection of the chassis, I discovered a very mangled tiny spring sitting on a motor magnet. This was clearly the pawl spring, which had somehow become entrained in the armature. No wonder the loco had recently failed to change direction when instructed.

The regulator rod had broken where the threaded section of the wire part screwed into the square-section brass .

New parts were ordered from the Club and supplied very quickly. (Thank you!)

Dismantling was challenging at times, but greatly assisted by Tutorial 016: https://www.youtube.com/watch?v=l29q4bZoU5A

One of the trickiest steps was the freeing-up of the steam pipe from the base of the safety valve, as some corrosion had cemented it in place. A watchmaker’s gear puller facilitated this, preventing damage to any steam-tight joints. After this, it became possible to loosen the superheater assembly from the chassis.

The new A4 regulator rod proved to be longer than the broken one by about 3mm and so didn’t fit.

Close examination revealed that it was in two parts, a short square-section brass piece drilled at one end with a ~1mm hole that just fits over the regulator operating gear’s vertical pin, as well as an M1 thread drilled into the other end. The other part was made from 1mm dia wire with a short angled section at one end and an M1 thread at the other. The original wire was brass and the Club-supplied part appeared to be stainless steel. I bought some K&S Metals 9861 Round Brass Rod 1mm, cut a piece to the right length and, using an M1 die, cut a thread into one end. It fitted.

The new pawl spring was fitted.

Before reassembly, test leads were used to apply 8V to the motor. It was very reluctant to run. 10V did work, but with much sparking. The motor and gearbox were removed from the chassis and then the motor from the gearbox. The brush assemblies were then carefully prised from the motor. They were almost seized with gummy oil. After cleaning, they were reassembled with a smear of Peco Electrolube and then replaced in the motor. The chassis was cleaned with isopropyl alcohol (IPA), followed up by aerosol printed circuit board cleaner. Axle bearings on the loco were lubricated with Labelle #102 gear oil. Gearbox and other steam-related mechanisms were lubricated with Hornby steam oil. Tender wheel bearings were lubricated with Peco Electrolube. The motor, gearbox and regulator now worked perfectly from the 8V supply.

The model was reassembled and tested. However, the PTFE seals on the steam pipe connection from tender to loco leaked. No spares were to hand so some 0.8mm thick fibre washers of appropriate internal diameter were ordered through Ebay from China. These worked well.

When next tested on my rolling road, another problem surfaced. The model started to warm up normally, but then cut out, as if the water had run dry. I suspected faulty control circuit issues and/or thermal cutout problems.

First, I gently re-soldered all circuits on the loco’s circuit board, to eliminate dry solder joints. No change.

Next, I replaced the tender thermal cutout with a new one purchased from Club spares. No change.

I then replaced the relay with an identical one bought in a batch from China. Still no change.

I then replaced the boiler heater with a new one. Still no change.

This is clearly an intermittent fault that appears when the model is warming up. Does anyone in the Club have any suggestions as to what I can do next?

Regards,

Rob Evans