Rectifier car (Gleichrichterwagen) 1 is numbered 7001 and is one of two which were built in 1944 but only officially taken into stock in 2006. It was previously Gleichrichterwagen 3 but despite having been renumbered as long ago as 1986 it is still possible to see evidence of the change.

It is acting as a mobile substation during the operation of the truncated 67 service to Per-Albin-Hansson-Siedlung, a service that will soon be replaced by an extension of the U1 subway.