Formations
The first two batches of 2BIL stock were subject to the EMU renumbering scheme implemented during January and February 1937. The renumbering of these units, and the original formations of all 2BIL units, are set out in the table below (*Unit 1890 was renumbered 1900 in January 1936):
| Units (pre-1937) | Units (post-1937) | DMBT | DTC |
|---|---|---|---|
| 1890 / 1900* | 2010 | 10567 | 12101 |
| 1891–1899 | 2001–2009 | 10568 to 10576 | 12102 to 12110 |
| 1901–1920 | 2011–2030 | 10577 to 10596 | 12034 to 12053 |
| 1954–1971 | 2031–2048 | 10597 to 10614 | 12054 to 12071 |
| - | 2049–2077 | 10615 to 10643 | 12072 to 12100 |
| - | 2078–2152 | 10644 to 10718 | 12111 to 12185 |
The first 10 2-BIL units 2001 to 2010 had an earlier form of multiple unit control. They were compatible with the 4-LAV units of the same era, but not with the remainder of the 2-BIL sets. They normally operating from Brighton, where the 4-LAV were also based, on local services. The remaining sets spent their lives on the services for which they were constructed, although they were fully mixed in operation, and it was common for units to be exchanged between areas of operation even within a day's normal work. Commuter services into London Waterloo, Victoria and London Bridge found them typically marshalled up to 8-car units.
An unusual feature of their operation in the 1950s and 1960s was that there were about 30 more diagrams for these units than sets actually existed, while for the subsequent 2-HAL units (class 402) there were more than 30 spare units, so a significant number of the daily 2-BIL diagrams were operated by the latter units, typically marshalled together as one of the sets in a full 8-car formation.
Read more about this topic: British Rail Class 401