The BCPM cars were built between 1916 and 1918. Some conversions into the class occurred in 1917 and 1920. The numbers for the BCPM cars were: 5 - 10, 19 - 23, 26, 42, 43, 49 - 92.
Cars 63 - 92 were built new 1916 to 1918. All other cars were converted from BCP_ between 1917 and 1920.
This class was relettered and renumbered between 1921 and 1923 to _M__. The cars were renumbered respectively from the above number group to numbers 298 - 303, 312 - 316, 319, 335, 336, 342 - 385.