With such a large production run over the years there were some changes made. All the changes are shown in a table, after an explanation.
Initially vehicles were built with four marker lamps on the cab front, three lower and one on top, corresponding to the lamp codes then in use. Part way through production it was decided to introduce a two-character train describer, sited below the centre cab window of driving cars. This resulted in the two centre marker lights being dispensed with while the two lower outer marker lights were retained. This modification took place from order 2f commencing with vehicles E50210 / E56062 being delivered in May 1957. However when the change was introduced vehicles already in production already had the cut-outs in the cab front for the four lamps. While the two-character box covered the lower cut-out, the top one was simply plated over in a crude manner. The table below shows "4" for four lamps or "2" for two lamps and a two-character train describer.
A variation which affected recognition of driving cars was that the earlier produced vehicles were equipped with a much longer vacuum pipe, rising to the top of the buffer beam. This was changed in February 1959 (order 4) when the first Leyland engined vehicle E51425 was produced with shorter pipes mounted at coupling hook level, all driving cars built after this date carried these shorter pipes. These are shown in the table as "L" for long and "S" for short (!). The Leyland engined vehicles are shown as "L" and AEC ones "A".
There were two designs of guards/loading doors. Batch two vehicles received left hand inward-opening guard's doors on both sides of the vehicle ("L" on the table). For the remaining vehicles these doors became "handed" with the inward opening door on the drivers side of the vehicle becoming the right hand door, the opposite inward opening door remained on the left ("H" in the table).
There was also changes to the interior of the van from batch four. The doorway through the partition from the passenger saloon to the guard's van was moved from the centre of the wall and repositioned to the second man's side. This enabled a security cage to be installed within the van leaving a passenger walkway along one side. The cage contained a sliding gate on the walkway side opposite the bodyside loading doors. On the table these are represented by "O" - open/original or "C" - caged/changed.
|Orders||Cab||Vac. pipe||Engine||Van door||Van|
|2a - 2e||4||L||A||L||O|
|2f - 2xa||2||L||A||L||O|
|4 & 5||2||S||L||H||C|
Description - Technical
Description - Variations
Description - Interior
Description - Modifications
Operations - Initial
Operations - Later
685 - Daisy
Details about preserved Class 101s can be found here.
Many thanks to Mac Winfield and Eddie Knorn for their assistance in the preparation of this section.