The B&O EM-1 was smaller than the UP Big Boy because it had to fit B&O's 1800s close clearances.
On a B&O discussion group there was a thread on how the EM-1s were delivered. Being it was during WW II, not much was publicly shown about them. Given their weight, even cold and empty as well as their size, the need for them to pass through the Howard Street Tunnel under Baltimore would have been a problem because of the third rail for electric helper locomotives on eastbound, up-grade trains.
Some one suggested EM-1 locos avoided Howard Street by crossing Baltimore Harbor on carfloats, as some new ATSF 4-8-4's did on their way west from Baldwin. Understand that most new steam locos were delivered cold, empty and with main and valve rods removed, being hauled like cars in a train.
Another commented about a photo of some new B&O EM-1 locomotives at Greencastle PA, on the PRR's Cumberland Valley line. At Hagerstown MD they would go via Western Maryland to a junction with B&O at Cherry Run on the Potomac River to reach Cumberland.
A few maintained that the EM-1 could not negotiate the old B&O mainline through Relay MD. Yet others said this was the route some took under steam from Brunswick MD Mount Clare for overhaul and run back west again (Overhauls could also be done at Cumberland).
In any event and even being 'smallish' against similar power, the EM-1 was still a sizeable machine. The lone EM-1 being saved for the B&O Museum collection ended up being scrapped in 1960. The road was too cash poor at the time to spare it.
EM-1 statistics:
Numbers 7600-7619 built in 1944 (renumbered 650-669 in 1956)
Numbers 7620-7620 built in 1945 (renumbered 670-679 in 1956)
Total length over couplers: 125' 3 5/8"
64" diameter drivers
Driver wheelbase 65' 2"
Fixed wheel base, each engine: 16' 9"
Lateral cushioning device on lead drivers of each engine and lead wheel set of the trailing truck.
Minumum curvature, slow speed, 18 degrees
Extreme height: 15' 11"
Extreme width over cylinder covers: 10' 10"
Total weight, engine and tender: 1,010,700 lbs.
Total weight on drivers: 485,000 lbs
Weight on front drivers: 244,000 lbs, weight on rear drivers 241,000 lbs.
Tractive Power 115,000 lbs
Factor of Adhesion: 4.22
Steam Pressure 235 lbs
Cylinders 24" x 32", 12" piston valves
Walschaert valve gear
ALCo Type H reverse gear
Grate area: 117.5 sq ft
Heating Surface (firebox and tubes) 5,298 sq ft.
Superheater 2,118 sq ft., Type "E"
Tender: B&O No. 32 tank on a No. 42 frame with No. 64 trucks.
Capacities: Water 22,000 gallons, Coal 25 tons.
Weight of tender: 382,000 lbs
Odd note:
The EM-1 whistle was a single bell 'hooter,' similar to what N&W's Y-6 class had.
