By the
1930's air conditioning systems were light enough to install on passenger cars.
Generally, diners were the first cars to be air conditioned as a measure of
cleanliness against soot from the locomotive. Pullman had placed an
experimental unit in the McNAIR, a 12-1 in 1929. The depression temporarily
stalled any plans, but Pullman had been through depressions before and would be
ready for the economic upturn. Initially only some cars were to be done. But
when a/c became a selling point, everyone jumped on the bandwagon and whole
trains were a/c'ed at one time. Pullman took advantage of their large pool of
skilled workers to upgrade their huge investment. Thousands of cars were air
condition during the 1930's, as well as hundreds that were rebuilt from older
section type sleepers into room type cars.
Ice
was originally used as a refrigerant. As it melted the water was piped to fans
in the ceiling and blown trough the car. Ammonia gas was used for a while, but
was too dangerous. Freon came into use in 1932. These cars all
had the Pullman-Mechanical type A/C with a brine tank installed on the dates
shown. (The brine tanks were later bypassed, and most were removed.) Glen Rae,
Glen Ridge and Glen Alta were also rebuilt to Plan 3523F when the A/C was
applied. |