Western Maryland 4-6-6-4 "Challenger" Locomotives in the USA

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The challengers on the WM are a difficult subject to cover. It seems no matter what you say about them somebody will have a different opinion. While the Wm challengers were used as helpers it simply is wrong to say they were not mainline fast freight engines. From their delivery until the arrival of the 4-8-4's the 1200's did exactly the job they were designed to do which was run through on trains from Hagerstown to Connellsville. Freight train speeds were a maximum of 50 mph between Hagerstown and Cumberland and 45 mph between Cumberland and Connellsville. The 1200's also occasionally worked trains east of Hagerstown to Baltimore but with this hilly and curving mainline and speeds limited to 40 mph they were not really at home there.

After the arrival of the 4-8-4's in January 1947 the challengers rarely ventured east of Cumberland. Most of these trips probably were to receive heavy shoppings in Hagerstown. While working almost exclusively on what was called the New Line the 1200's did often work as helpers but so did every other type of motive power working on Sandpatch grade. It is important that there were no divisions on the WM that did not have a helper district so the railroad got very good at using power as helpers. In the case of trains over Sandpatch this often meant mid train as well as rear end helpers to distribute power. To this end some of the helpers being used on westbound trains up would either stay on the train all the way to Connellsville or cut off and follow the train. If you see a rear end helper that is shoving on a caboose and also has one trailing behind the tender that crew is going on to Connellsville and will bring another train back east. This sometimes resulted in trains with an older Decapods on the head end and a challenger trailing as a rear end helper. In fact the Decapods and challengers seemed to be used almost indiscriminately on these assignments. As proof the challengers were mainline power to the end I offer several pictures by famed photographer Bill Price of Cumberland in the book Fireballs and Black Diamonds. These pictures, captioned the last challenger were taken June 7 1953. They show engine 1211 leading yet another westbound train out of Cumberland and up Sandpatch with mid-train helper Decapod 1130 and shoving on the rear is 4-8-4 number 1404. Only 1210 and 1211 remained on the roster that June.

When talking to WM men there seemed to be only 2 opinions of the challenges. Either they liked them or they hated them. Many complained about the challengers being rough riding but when pressed these guys would confess that was only when compared to the Pacifics and Potomacs, WM's name for their 4-8-4-s. Others complained about the articulateds being slippery while a few said you just had to know how to run them. One veteran engineer told me he was always afraid of going though some of the tunnels because of how close the front cylinders got to the walls when swinging. It is very difficult to get a handle on just how these locomotives actually performed.

When comparing the WM Challengers to those of other railroads the first conclusion you come to is that there were basically 3 sizes of challengers. Most, like the WM, D&H, CRR, WP and early UP engines, were the small challengers and the rest were either medium or the real heavy weights of the type. Frankly the specifications for all the small challengers were nearly the same. The biggest difference was some had higher steam pressures with the D&H taking the top honors with 285 psi. The higher steam pressure resulted in smaller cylinder diameters. These engines had the advantage of getting more work for less steam, read fuel and water, than the WM engines which only carried 250 psi but several other challengers also carried 250 or 255 psi. The specifications for the WM engines seem to be almost identical to those of the first UP Challengers.

The WM challengers could have benefited from a number of improvements, not the least of which would have been roller bearings on all axles. WM's first experiment with roller bearings was on the lead truck of the 1200 and in 1940 most railroads still considered roller bearings only worth the investment on passenger locomotives. Many of the other small challengers also had solid bearings. Type E superheaters would have contributed considerably to the efficiency of the 1200's like they did for their later 4-8-4's but looking at the site I do not see an obvious application of Type E superheaters to any of the small challengers. The heating area of the superheaters on the WM engines was right in the middle of the other comparable engines but less that that of their later 1400's. As mentioned earlier, higher steam pressure would have resulted in more power and less fuel usage. Trailing truck boosters would have added to the low speed abilities of the engines. Had the WM engines been built by Alco they likely would have incorporated the new design weight supporting hinge which would have put more weight on the front engine as well as improve the riding qualities of the locomotives. Of course, like everything else, all of these improvements except the roller bearings would have come at a cost of increased maintenance expenses. As an example the UP decided Type E superheater units were not worth the extra maintenance and did not order them on the last batches of 4-8-4's and apparently the challengers as well.

The railroad never seemed to be satisfied with the challengers. To be honest it is difficult to determine just what they wanted from these big engines or if they really understood what they were designed to do. If they wanted engines that would speed up fast freight operations they got them. The railroad was always looking for a locomotive that could handle the same train over the mountains and run with it on the relatively flat track between Hagerstown and Cumberland. Practical application tells you that the only way to do that is to drastically overpower trains on the level or add locomotives for the grades. Truthfully with the challengers WM probably achieved both. The 1400's proved the same trains could be handled over the more level track with smaller engines and train speeds were affected by nearly all trains having to stop and add helpers both mid train and on the rear to get over Sandpatch. In the end the WM seemed to decide, and correctly so on a mountain railroad, that tractive effort was more important than horsepower.

Much has been made of the fact the Challengers were the first class of engines to be scrapped in total by the WM. I have concluded this is probably a case of unfortunate timing more than a statement of what they thought of the locomotives. Steam locomotives by the laws of the time came due for flue replacement and heavy shoppings every 4 years. Simple addition brings the obvious conclusion that all of these engines would have come due sometime in 1952 or 53. The order came down in 1952 to cease all heavy repairs of steam engines and those needing heavy repairs would be retired. It would seem the challengers were doomed early by this order.

What conclusions does this leave us with? For what my opinion is worth I think the WM challengers were not a lot different in performance than any of the rest of the small challengers. They performed every task they were designed for. Remember that WM was not the only railroad that did not always use their challengers for their designed purpose. The D&H used their challengers frequently as helpers with as many as 3 of them slogging up steep grades at 10 or 15 mph on 1 train. Since the D&RGW challengers were the other challengers built by Baldwin and the first preceded the WM engines by several years it is difficult to believe Baldwin incorrectly balanced the WM engines. It is reported the Rio Grande was using one of their new challengers in passenger service in the late thirties at speeds up to 70 mph with no problems. It is often stated the WM would have fared better with 2-8-8-4's similar to the B&O EM-1 and I think there is a lot of truth in this conclusion. The EM-1 had nearly 20,000 pounds more starting tractive effort than the WM challengers and would have performed well on the WM. The EM-1 was used to run coal trains into Hagerstown on a regular basis so WM men had a good comparison of the capabilities of both locomotives. While the EM-1 did have roller bearings on all axles they were hampered by a very low 235 pounds of steam pressure. Like the WM challengers the EM-1 would have benefited with higher steam pressure and smaller cylinders. Remember to that the EM-1 was designed nearly 5 years after the WM engines and with B&O holding a controlling interest in the WM may well have benefited from the experience of the WM with their challengers. Then again the B&O bought high speed 2-6-6-4's from the Seaboard Air Line after WW II and ran them between Cumberland and Brunswick as well as into Hagerstown on the WM. This basically happened on a line parallel to the WM at the same time WM banished their challengers to the mountains.

One thing the challengers did for the railroad that can not be disputed is that they gave the railroad proof it was in the fast freight business. Regardless of the limitations of the locomotives themselves or their contribution to speeding up freight trains salesman had a locomotive with big drivers they could show customers and potential customers. After all, every little boy at the time knew big drivers meant fast engines. How important was this to the WM? In 1952 they published a booklet to help celebrate the 100th birthday of the railroad. The challengers, Potomacs, and diesels were all featured in the booklet. However, it was a builders photo of challenger 1203 spread across two pages in the top center of the booklet that was most prominent. How does this prove the challengers to be important to the image of the WM? With the decision already made to dieselize the railroad challenger 1209 was stricken from the roster in August 1952, three months after the official celebration.

Information provided by John Bohon.


Roster by Richard Duley

ClassQty.Road NumberYear Built Builder Notes
M-2 61201-12061940BaldwinNumbers 1201-1206 scrapped in 1953
M-2 61207-12121941BaldwinNumbers 1207-1212 scrapped in 1953

Class Details by Steve Llanso of Sweat House Media

Class M-2 (Locobase 342)

Data from 1947 Locomotive Cyclopedia, supplemented by WM Misc Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also Bert Pennypacker, "Challengers Over the Mountains", Trains (April 1992), pp. 49-54. The diagram shows that the Baldwin works numbers were 62453-62454 in November 1941, 62455-62456 in December, 62457-62463 in January 1942, and 62464 in February.

Firebox heating surface included 252 sq ft (23.41 sq m) of thermic syphons (5) and arch tubes.

Worked the Hagerstown-Connellsville section, which has a 23-mile (37 km) grade measured at 1.75%. M-2s showed a dynamometer rating of 4,700 drawbar horsepower at 50 mph (81 km/h), at which point it was indicating approx 35,000 lb of tractive effort. (The J-class 4-8-4s were not far behind at the higher speeds.) When worked on the descending grade of 0.3%, an M-2 could haul 8,000 tons of merchandise train, 10,500 tons of coal cars.

Bert Pennypacker noted that the placement of the front truck directly under the smokebox was unusual. Other construction notes (from Pennypacker):

-- Three Duplex thermic syphons in firebox, two in combustion chamber;

-- Standard HT automatic stoker;

-- Flexible staybolts in several points;

-- Type A superheater with American multi-valve throttle;

-- Hancock injector, Worthington feed-water heater, Barco low-water alarm.

Yet Pennypacker said that these engines were known as slippery and hard-to-handle brutes. He suggested that the problem arose from "misplaced expectations". The design (high drivers, light axle loads) wasn't really suitable for WM's style of heavy running, although other railroads used Challengers in similar service. The WM, he concluded, "probably would habe been far better off with the likes of an engine such as B&O's husky and outstanding EM-1 2-8-8-4 [Locobase 333]," which could have "boosted all tonnage rating by at least 1,000 while offering a 50 mph capability in the Potomac valley."

Specifications by Steve Llanso of Sweat House Media
ClassM-2
Locobase ID342
RailroadWestern Maryland (WM)
CountryUSA
Whyte4-6-6-4
Number in Class12
Road Numbers1201-1212
GaugeStd
Number Built12
BuilderBaldwin
Year1940
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)12 / 3.66
Engine Wheelbase (ft / m)60.33 / 18.39
Ratio of driving wheelbase to overall engine wheebase 0.20
Overall Wheelbase (engine & tender) (ft / m)106 / 32.31
Axle Loading (Maximum Weight per Axle) (lbs / kg)67,562 / 30,646
Weight on Drivers (lbs / kg)402,266 / 182,465
Engine Weight (lbs / kg)601,000 / 272,609
Tender Loaded Weight (lbs / kg)418,950 / 190,033
Total Engine and Tender Weight (lbs / kg)1,019,950 / 462,642
Tender Water Capacity (gals / ML)22,000 / 83.33
Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)30 / 27.30
Minimum weight of rail (calculated) (lb/yd)112
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)69 / 1753
Boiler Pressure (psi / kPa)250 / 17.20
High Pressure Cylinders (dia x stroke) (in / mm)22" x 32" / 559x813 (4)
Tractive Effort (lbs / kg)95,397 / 43271.40
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.22
Heating Ability
Firebox Area (sq ft / m2)796 / 73.98
Grate Area (sq ft / m2)118.80 / 11.04
Evaporative Heating Surface (sq ft / m2)5770 / 536.25
Superheating Surface (sq ft / m2)1735 / 161.25
Combined Heating Surface (sq ft / m2)7505 / 697.50
Evaporative Heating Surface/Cylinder Volume204.92
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation29,700
Same as above plus superheater percentage36,531
Same as above but substitute firebox area for grate area244,770
Power L125,898
Power MT851.60

Reference