sentences:  Built for the Jubilee Line extension of the London Underground in 1994 and used by the contractors who re-laid the entire line in conjunction with the IRIS project (a sewerage scheme which saw a main pipeline being laid beneath the railway in 2000-2002 resulting in shuttle services being operated), this locomotive was bought from the contractors upon completion of the work and named "Ailsa" in honour of Archibald Kennedy, 7th Marquess of Ailsa who had done so much to keep the railway alive in the late 1960s.It was stated at the time that the loco would receive a spring green livery (known as "Ailsa Green" as it was standard livery at the time of his ownership) but it remains in plain white livery to date.The locomotive was originally built to work on the construction railway in the Channel Tunnel which accounts for the somewhat squat appearance.