Class 360 Heathrow Connect

[D365]

They were rebuilt from the Class 350/0 prototypes, is probably the simple answer.

 

[JN114]

Why were the Heathrow 360s ordered with 5 20m cars, when the other 350/360/450s are all 4 cars units, and the HEx 332s 23m cars? Was this the maximum length that could fit on some of the intermediate platforms?

They were delivered as 4 x 4 car units. A 5th, 5 car unit and additional trailer vehicles to make all units up to 5 car arrived a couple of years later.

 

[Mikey C]

They were delivered as 4 x 4 car units. A 5th, 5 car unit and additional trailer vehicles to make all units up to 5 car arrived a couple of years later.

Thanks. It does make them rather non standard...