Looking over my and other folk's photos from the recent John Craft charter has me pondering the N&W and its 4-8-0s.

My chief question: what was it about this oddball wheel arrangement that so appealed to N&W? Most contemporary roads ca. 1900 seem to have been very happy with the 2-8-0 as a mountain-slayer. Some, like Western Maryland and D&H, stuck with the Consol for mainline drag service in mountainous terrain almost to the end, growing the design to gargantuan proportions.

Yet N&W seemed to like its 4-8-0s, and explored the potential of that arrangement even as other roads were ordering 2-8-0s en mass.

So what was the charm of the design for Roanoke? Were there axle loading constraints that required transferring a bit more weight off of the four-coupled driver set? Did N&W feel the four-wheel pilot truck tracked better, or was easier on the road? Was it just a matter of a CMOs taste?

Idle minds would appreciate learning...

Interesting question, Eric. If you look at the specifications of the Class M, it is essentially a "sliderulered" Class W 2-8-0, with a larger boiler. I have seen the same basic question asked about why "M"s when other roads were getting 2-8-2's, and the answer was given as liking the 4 wheel lead truck for tracking, and keeping plenty of weight on the drivers for adhesion. They must have been a good performing design, otherwise the N&W wouldn't have kept them around until dieselization in the numbers that they did.

N&W was pretty happy with 2-8-0s, to the point of buying 277 of them.

The 4-8-0 beat out the 2-8-2, not the 2-8-0. (N&W never bought one.)

Lewis Jeffries speculates that when N&W compared the 4-8-0 and the 2-8-2, that the 4-8-0's greater proportion of its weight on drivers, and the 4-wheel truck's performance on the many curves, won out.

Later, N&W went straight to the 2-6-6-2.

JAC

Thanks, Gary and John.

The "better adhesion and tracking than a Mike of comparable power" explanation makes sense. Even so, I still suspect that somewhere at the bottom of it all was a mix of intuition and cussedness on Roanoke's part as much as steeley-eyed rational engineering. But hey, ideosyncracies like this are what makes steam so fascinating.

Erik:

The N&W took the original M class Twelve-Wheelers and made a "better" class M1 (which wasn't liked) and then an M2 (which was.) The M1 proved that, though the N&W may have liked the 4-8-0 type, it wasn't above getting rid of its failures.

Les

Though it is sometimes hard to remember 85 years later the Western Maryland did not originally buy their huge H-9 class 2-8-0's for drag service. They were designed to replace older 2-8-0's and plodding 2-8-8-2's with small tenders in fast freight service. Since the opening of the new line to Connelsville and the overhead connections to the west the WM had been searching unsucessfully for a suitable fast freight locomotive. Their 61 inch drivers and big tanks allowed them to get over the road in good enough time to make a turn from Hagerstown to Cumberland and return in less than 16 hours with almost any train the railroad could run. Their big boilers produced about the same horsepower as a USRA mike and their weight on drivers gave them enough tractive effort to eliminate many doubleheaders. The 800s served in fast freight service until the challengers replaced them between Hagerstown and Connelsville in 1941 and the 4-8-4's replaced them on the pool trains to Rutherford on the Reading in 1947. Perhaps the best evidence that the H-9 was not designed as a drag engine is that the crews that ran them in drag service on the Elkins line considered the engines slippery. They much perfered the 52 inch drivered H-8.

The comment about the M being a sliderule engine also hits home with the WM. When the H-9 proved to be to small to handle growing trains on Sandpatch the railroad went to Baldwin for 20 huge decapods. The decapods had the same 61 inch drivers as the consolidations but almost every other major dimmension was one third larger than the same dimmension on the H-9. This even included the capacities of the tender. Apparently the railroad was very satisfied with their old fashioned fast freight engines. The same could not be said for the new challengers though the 4-8-4s were considered the best locomotives the WM ever owned by almost everyone.

John Bohon

Interesting, John--I had no idea the H-9s were designed for that service. Many thanks!

Les, As a Roanoke native, and a member of an N&W family, I have to take exception to your "good" & "better" definitions of the various class M's. The original class M consisted of 125 locomotives, 75 from Alco Richmond, and 50 from Baldwin. All were originally built with Stephenson valve gear in 1906. The M1 class consisted of 100 engines, split 50/50 between Richmond and Baldwin, all built in 1907 with Walschaerts valve gear. This was the only difference between the two classes other than the location of the check valves. By 1920 N&W had standardized on the Baker valve gear on all of it's newer motive power, and the original M's were being retrofitted with the Baker gear as they were shopped. Also by the mid 20's, all of the M's had been downgraded from mainline drag service by the N&W's almost exclusive use of articulateds in both drag and time freight service. The M1's were just as good a locomotive as the M, however, as the need for that size of motive power decreased, the railroad naturally retired the ones with non-standard components first, other considerations being equal. The M2 class consisted of 61 locomotives, 50 by Baldwin, and 11 by Roanoke Shops, built between 1910 and 1912. They were 11 tons heavier than the earlier M's and had 12,000 lbs. more tractive effort. The Baldwins were all built with Walschaerts gear, and the Roanoke built engines had Baker. The M2's were built as drag and time freight locos, and were considered to be a successfull design. However, like the smaller M's, they were quickly surpassed in heavy freight service by the Z class 2-6-6-2's and the Y class 2-8-8-2's. Like the other M's, they led long service lives in local freight, switching, and branch line service. A higher percentage of the Roanoke built engines survived until dieselization, but I don't know whether it was because of the "standard" valve gear, or because East End Shops simply built damn good locomotives. The N&W did have some unique locomotive designs, but they were tailored to the operating conditions of the railroad. At it's peak, this philosophy produced the A, the J, and the Y6, and steam's "Alamo".

Gary-

Thanks. I stand corrected.

Les

I've never paid much attention to N&W's rosters, but it did always seem like something was missing. I guess the Mike was it. It just seemed like they went from modest 8 coupled locomotives to articulates rather fast. Aside from the J's and K's and a few pacifics, they seemed to nothing but smaller locomotives, and bigger locomotives. Maybe they skipped a wastefull step in locomotive development??

Other than the four wheel lead truck might be a bit simpler than a two wheel - and definitely simpler than a 2-8-2, I don't know why they liked the wheel arrangement so much. They must have been prone to derailing the lead truck since they had a wiggler valve attached to the frame and the wiggler protruded into a frame on the lead truck. If the truck moved too far up, down, or sideways, the valve dumped the trainline. Obviously the mindset was "when it derails" rather than "if it derails".

Was this device standard on the M's or just on the engines on lines with more curves, bad track, etc.?

Linn, First off, I claim immunity from the accuracy of this reply due to age and CRS, but I have seen mention of the "wiggler" device in an article in the N&WHS newsletter a few years back. The photos, if I remember correctly, were of it fitted to a Y5 or Y6. Again, going back 25 years when I worked at a certain museum in Virginia, I seem to recall seeing such a device on the lead truck of a well known 4-8-4, as well as a 2-6-6-4, before both locos spent some time in mainline excursion service. Perhaps some of the guys who worked in Birmingham from 81 till 87 can comment. In my opinion, I think the N&W was the victim of a good appliance salesman.

The "wiggler" is a facinating idea that I have never heard of before. Did other lines use it besides the N&W? I wonder how often, it dumped the air in day to day operations. I guess it would establish the speed limit with a practical certainty.

RTK