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Are there any other significant differences between the 2-8-8-4 Yellowstone and the 4-8-8-4 Big Boy other than wheel arrangement? I must admit that for a long time I had the two confused as the same engine. Slowly, I am learning........

 

Also, it appears that the B&O was the smallest Yellowstone of the lot??

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Anybody out there kind of an expert on this?

 

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Weight for the two locos is hugely different, with the UP at 778K Lbs for the loco

alone, and the B&O EM1 at around 628K Lbs. less tender.  The UP is also taller

and longer as well.  The Big Boy was designed as an all-out effort steamer to

conquer the Wahsatch Mountains east of Ogden, Utah. UP had few weight

restrictions and big clearences.  The 4000s were built big to eliminate the need

for helpers on this route...which didn't quite work out.

The EM1 is a totally different animal, and would have been an EMD FT order had

circumstances been only slightly different.  As it was B&O and Baldwin got together

and designed a steamer that at the time could go head to head with a two unit

set of FT Diesels...in almost every category!  Many people criticize the B&O for

building such an uninspired articulated design. In reality, the EM1 is highly

misunderstood, and underrated.  This design was, in it's own right and context,

as outstanding as the Roanoke machines of fame and fortune! One has to understand that B&O was a Diesel operation at this time, and the newly bought

steamers were designed to fit into their Diesel way of thinking, both in terms of

operation, and finances. It worked amazingly well right up to the very end of

B&O steam.

As I understand it, the EM-s1 were indeed the smallest locos made with the Yellowstone wheel arrangement , but then its still a fairly impossing loco.  I don't have mine yet (should pick it up this weekend, I expect) but I've seen older models alongside scale Big Boys.   The EM-1 is slightly smaller -- maybe 1/2 inch shorter or a bit more, just a tad lower and not as fat in the boilers, etc.  But I think it still has noticeably more "gravitas" than, say, a Challenger . . .  

The Yellowstone is an older class of locomotive. It was developed and designed by the  Northern Pacific Railroad. I want to say around 1928 it appeared on the scene. Alco built the first one and hosted a dinner inside the fire box boasting the largest fire box of any locomotive. It was made to burn Rosebud coal. A type of coal that was almost like just plain dirt. At this time the Northern Pacific Z-5 Yellowstone was THE largest locomotive ever built.

People said in Livingston that when this engine came into town, the ground shook and basically everyone stopped what they were doing to see this intimidating-thundering beast through the yard. This must have been something.

 

The EM-1  - shares the same wheel arrangement of a yellowstone but really is not a Yellowstone. Its drivers, smoke box, tender, cab, boiler size, fire box, are totally unique.The DMIR Yellowstone is a closer copy.

Its sort of like saying the AC-9 was a Yellowstone... no not really. It just had a similar wheel arrangement.

 

The Big Boy on the other hand really belongs in it own class. Its more of a super steam engine / modern design of an engine. It was developed and designed and the first engine was released in 1941, almost 18 years after the first Yellowstone. As a matter a fact the Z-5 Yellowstone was pretty much used as a helper at that point on Bozeman pass in Montana. It could not keep up with the higher speeds of the Challenger Z-6.

 

For reading/photos that you really may enjoy:

 

The Northern Pacific Railway of McGee and Nixon: Classic Photographs of Equipment and Environment During the 1930-1955

Amazing photos from two incredible gentleman. I believe Mr. McGee still is alive and well and lives in Livingston, Montana.

 

http://www.amazon.com/Northern...-Nixon/dp/0915370034

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.

 

 

 

 

 

 

 

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