The PRT plows and sweepers were built in 1923 and the plows converted to sweepers in 1926. Most of the single-truck sweepers were built before 1910, when trolleys were smaller and thus the DT sweepers paralleled the development of larger passenger trolleys.

The DT 1923 cars ride better, have room for the spreader wings amidships and with four motors have more power to buck snow or climb hills.

Red Arrow's later sweepers were double truck as were Toronto's.

Phil Mulligan