SP DRSB-6-6-1500 page: Renumberings

Renumberings:

This unique-on-the-SP-model was renumbered several times over its service life.

SP 5227, 5500, 4900:

Original number	1950 number	1955 number	1965 number
SP 5227	SP 5500	SP 4900	SP 4900