After acquiring its first road switchers in the first half of the 50's, the Canadian National Railway renumbered many of them up to tree times in less than four years. Here is an example for a GP7:
GP7, serial A-555 shipped from GMD 30 November 1953 as 7576;
renumbered 1721 in September 1954
renumbered 4371 in June 1956
renumbered 4821 in August 1957
A locomotive being profitable when on the tracks, not in the paint shop, what was the need, or the purpose, of those repeated renumberings?
Guy
Modeling CNR in the 50's
Most likely to free-up number groupings for recently-acquired or soon-to-be-acquired locomotives. Keep in mind, too, that the CNR still had active steam locomotives at this time, and they had already gone through re-numbering process.
Wayne
They would repaint the number while it was in the shop for something else. an engine wouldn't see a "paint shop" unless it was being completely rebuilt.
During the mergers in the 1990's, I know of engines that were renumbered more than once while they were still in the rebuild shop. They were renumbered before they even got painted.
Dave H. Painted side goes up. My website : wnbranch.com
Employee timetables would set load and speed limits on engines by number class. It may even be that pay scales were triggered by number class. So it was important for the numbering system of an identical class of locomotives to make sense and not be scattershot.
Dave Nelson