None of the rotaries are self mobile since origianl building and require pusher locomotives. The rebuilt plows benefit form the ability to mate locomotives. The arrangement has been basically the same for all the electric rebuilds since the CB&Q (BNSF 972558) rotary in Lincoln was the first to be rebuilt after the 1949 snows. They must not have been completely convinced on the idea though because they chose to do extensive rebuilds of their Alliance, NE plow and their C&S plow at the same time but stayed with steam. Both of those plows were completely reconstructed with some of the blade and shaft components being the only thing retained.
BNSF 972558 has been stationed in Lincoln, NE since it was purchased by the CB&Q in October of 1915. It was rebuilt to Electric by the Denver shops in Dec of 1949. The plow was heavily damaged in South Dakota March 2001. It sat in Lincoln with the blade completely destroyed and the broken remains of the hood for many years. It was sent to Relco for work completed in December 2010. It was painted in the new BNSF colors at that time. Rotary Snowplow Power Unit 972573 (ex BN F9B #775) is permanently assigned to to this plow. The plow was sent to MN March of 2011 to replace the 972551 that was heavily damaged in, you guessed it, South Dakota but is reported to not been actually used.
BNSF 972559 was a Copper River & Northwestern rotary built in Sept 1915. The NP bought three of their 4 plows in October 1941. It was #46, rebuilt to electric in 1966 and numbered #47. Stationed in Alliance, NE since Sept 1986,it has been one of the most used rotaries for years. It was sent to Relco for work and as a pattern for the 972558 repairs. returned to Alliance with new BNSF colors in December 2010. It has been assigned RSPU 972572 (ex BN F9B #769) for years.
The SP plows have B unit power cars also. The SPMW 207 and its power car were rebuilt at Relco and sent back to Roseville in 2013, Used on Donner March of 2016 and February of 2017. It was built for the SP in 1926.
Others like the Glendive plows do not use the power cars. although RSPUs are stored there.
The last Class 1 use of a steam rotary was the 900076 in March of 1977. It was loaned to the Rock Island and used in Northern Colorado. The Rock Island had retired its almost identical plow in March of 1966 when it was only 16 years old. Interesting to hear the 900076 was almost used in 1980, It was active until being retired June 1985. The plow is now on display with another UP (ex MILW) rotary in Hermiston, OR.
I don't know enough about UP operations but were their plows kept steamed up all winter? The D&RGW kept all the NG plows hooked to RH steam up and inside (OM had to sit out in Chama) all winter since the 20s
