Motherwell Power Signal Box - Panel Clocks

During the 80's and 90's the ScR Electronics Section provided panel clocks for Paisley PSB and Motherwell PSB. Now in 2023 about four years after the closure of Motherwell PSB (control passed to the West of Scotland Signalling Centre) the panel clocks have re-surfaced.

Normally it is very easy to identify the year a small project was installed as the serial numbers include the year. In this case there are some other dates that contradict the serial numbers. The serial numbers run from 92-02-01 to 07 but the TX clock and LED matrix PCB's are dated 1993 and the software 1994! My guess is that the project started at the end of 1992 and was completed in 1993 with a software update (probably to improve time keeping) in 1994.

So the clocks at Motherwell were used 24/7 from 1993 (best guess) through to the closure in 2019, twenty six years of non stop operation.

The clocks were designed around the standard ScR Train Describer display units with one converted and programmed to display the time and then to transmit that time to the other displays thus ensuring they're all synchronised.

There were eight clocks built for Motherwell PSB, one for each panel and a spare. All were powered from the panel 110V AC supply. The main Clock was positioned on the centre panel and data cables were looped left and right to the secondary displays.

The original documention can be found here, SES Clocks and my recreation of them as my workshop clocks in 2021.

The un-earthed clocks

Seven of the Clocks have survived, a bit dusty but they're in not too bad condition for their 30 years.

The cases all show signs of ageing with most having cracks and pieces broken off.

The main Clock has a micro-controller daughter board which replaces the TD display micro-controller. In addition to the clock program this daughter board has two differential drivers to transmit the time data to the secondary displays and the terminals for the time set buttons.

The clock design was partly borrowed from previous projects such as the Section Failure Locator from 1981 and the Train Describer from 1983. The PCB's from back to front:

SES81/7 the power supply, 110V AC to 5V DC. This PCB was reused from the Section Failure Locator. and is shown below.

83SES4 the third design of our Train Describer Display Module as used from High St TD onwards.

93SES3 The Clock TX Board. Made in-house.

93SES1 Dot Matrix Display.

The secondary clocks were effectively very large Train Describer displays!

The software versions: Display Module V1.1 CSUM BD0B and the TX Module V1.0 F0F6. All SES software is listed here.


The cases are in a bit of a state with dirt, scuff markings, cracks, bits missing and probably in the need of retro-brighting. I'll look at cleaning them up as much as possible and to test them I'll need to get a 110V supply..a job for when my new workshop is ready.