Headcodes

Introduction

Many DMUs were build with one, two or four character headcodes as a means of identifying the working to staff, particulary signalmen. They replaced earlier methods such as lamp codes, which the earlier builds of DMUs had.

The single digit headcodes used stencils, these slid into the headcode box via a flap at the top, with the unused characters being kept in the cab. The two and four character headcodes used roller blinds, adjustable via handles in the driver's compartment with flaps that opened so the driver could see what was being displayed from behind. All types were illuminated from behind.

The 79xxx series Swindon Inter-City DMUs were the only type to have a single character headcode. Initially an A, B, or C would be displayed to denote the train classification, this later changed to a 1, 2 or 3.

On the "intermediate" power cars, with a gangway at the cab end, there was a headcode on either side of the gangway.

The two character headcode is also sometimes referred to as a Route Indicator. These were always below the centre cab window.

Around spring 1959 vehicles began to be delivered with a four character headcode, instead of the two-digit version. Normally these were fitted to the cab roof dome, the exceptions being vehicles built at Swindon and the Gloucester parcel cars.

During the early part of the refurbishment programme some vehicles treated received a mini four character headcode in the left cab window. The vehicle in the image had been built with a two-character headcode, this has been removed and plated over.

The requirement to display the codes ended at the start of 1976, at which point a directive was issued for them to be wound to display zeros or blanks and the handles be removed. Many would in time be replaced by the "Dominoes" (the large white dot on black) or removed and plated over.

Producing a list of headcodes isn't an easy affair, due to the volume and changes over the years. One of the most dependable listing of these is in the staff Working Timetables, the introduction of these had a summary, with the actual headcode for each train given in the tables. These pages will feature the summmaries as guide to what the workings should be for a headcode.