Chesterfield's Mystery Engine!
Long explination.
About 6 months ago, the career staff was moved out of Fire Station 10 due to a horrible mold problem in the career area of the station. Because Station 10 owned by the volunteers, the volunteer engine (E210) and brush (B10) remained there, while Engine 10 and Medic 10 were moved to Manchester Rescue Station 1 (Courthouse & Hull St).
It's now been decided that the career staff will NOT be moving back to FS10, therefore, E10 and M10 have been re-designated E24 and M24, and will be moved to Station 24 whenever that's built. Until then, E24 and M24 will continue to run from RM1.
E210 has been re-designated E10, and will only be dispatched on calls when staffed. Otherwise, E20 and E24 will cover the calls in E10's first due.
On a related note, if you hear "Engine 23" on the Chesterfield radio, it's actually Engine 224 from DSCR down on Jeff Davis.
Hope this helps...