These cars are basically flat cars with National Car Co.
reporting marks that held two removable Borden's, Renkin's,
Dairyman's League or Sheffield milk tanks.

Users of these "demountable" tanks also included Muller Dairies
(shipping over the NYO&W from Norwich), and also Jetter Diary
in at least a short term experimental trial.

Sheffield shipped its fluid milk primarily in GPEX tank cars, both
leased ("GPEX") and owned outright ("SFCX"). shippers using
demoutable tanks generally were those located such that a
truck link was needed from rail to processing plant" --
(Muller - east side of Hudson from rail destination at
Weehawken, NJ) (Jetter - also East side of Hudson -
Bronx) and (Renkin's - Brooklyn, with fluid milk from
western Connecticut).

Most Sheffield plants were located immediately on
sidings so that a truck link was not needed at least
for the inbound fluid milk, and therefore did not make
use of demountable tanks, if at all.

While the N.X. BMT cars were indeed "basically flat
cars" they were quite specially appointed. Some had
end railings (some did not). There were cars for the
twin 3,000 gallon tanks (as are the F&C models and
earlier brass offerings from OMI), but also 40' cars
for a single 4,000 gallon tank (most commonly used
by Borden's). Some cars were equipped fro passenger
train service with steam and signal lines, but some were
not. All cars were lacking stake pockets and had flush
folding bracket on the sides for tying down the truck
rack and chain driven unloading apparatus on the
trans - ship trucks.

Mal Houck