In 1937 the London and North Eastern Railway (LNER) received articulated twin passenger electric units to replace the NER electric units that had been built in 1904–15 by the North Eastern Railway.

The original NER electric units built in 1904–15 were replaced with 64 new articulated twins, 112 feet 7 inches (34.32 m) long, and two luggage vans.

The passenger cars had bucket seats and manually operated sliding doors.

Built by Metropolitan-Cammell, the trains ran on a 600 V DC third rail system.

Electro-pneumatic brakes were fitted; the trains had a pneumatic sanding system.