One set would remain here, for use as a reference.
This set remained in circulation until November 11, 1944.
This set remained in use until 1949 during which time it went through many different printings.
Units were gradually removed from traffic, and by March 2004 only three sets, 312718/721/723, remained in service.
The first set remained in use for almost 20 years, before the second publication in 1953.
That set of suggestions has remained pretty much constant over the half decade.
The set remains in use and is a major tourist attraction.
No mistake: people grow and change, but the set of the eyes remains.
However, the complete set of available commands remains in the active memory of the computer.
As of December 2012, three 3-car sets remained in service.