These units need to be coupled in a certain way to operate and not invalidate warranties.
The whole unit is powered throughout, it is imperative that consumers read the instructions carefully before coupling the units prior to running them on any layout.
The 4 CEP needs to be connected in the correct sequence otherwise the electrical polarity that drives the EMU can be affected. Full instructions will be enclosed with each model, clearly showing the correct method of assembly.
The British Rail Class 411 (or 4 Cep) electrical multiple units were built at Eastleigh works from 1956-63 for the newly electrified main lines in Kent. These units were based on the earlier Southern Railway 4Cor design, built in 1937. A total of 133 units were built, as two different types. The majority of units were 'standard' passenger-only units, complemented by units containing a buffet car. The standard units contained passenger seating only, and formed the backbone of the new fleet. 111 units were built in several batches, initially numbered in the range 7101-7211. Units 7101-7104 were the prototype units, and were followed by 'Phase 1' units (7105-7153) and subsequently 'Phase 2' units (7154-7211). Units were formed of two outer driving motors cars, sandwiching two intermediate trailer cars.