Chicago & Western Indiana 2-6-2 "Prairie" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 100 (Locobase 472)

Commuter tank engine with outside slide valves, inside valve gear. Data from Bruce (1952) and AERJ Feb 1902. See also "Double Ender Tank Locomotive", Railway and Locomotive Engineering, Volume 18, No 3 (March 1905), pp. 119-120; and E E R Tratman, "Tank Locomotives", Official Proceedings of the Western Railway Club, Vol 17, No 8 (18 April 1905) (Chicago: W F Hall Printing Company, 1905), pp. 342 et seq. Works numbers were 6243-6245 in October 1904.

There are intriguing similarities between these engines and those built by Baldwin for the CNJ in the same year and the Long Island in 1904 (for the latter, see Locobase 9078). The boilers are identical in length and number of tubes, weights are very nearly identical, power numbers are the same. Only the grates are different with the C&WI carrying a shorter, narrower grate. Also, the CNJ's firebox heating surface, which is actually a bit less than that of the C & WI, included arch tubes.

The trio pulled 2-4 car trains between Chicago and Dolton, making 15 stops in 16.6 miles ( 26.7 km) miles. Tratman noted that the side tanks gave a variation of 30,000 lb (13,608 kg) in adhesion weight, but that even at the lowest water levels, the locomotive's factor of adhesion didn't drop below 4.4.

PH Peck, commenting on the Tank Locomotives paper referenced above, gave a detailed summary of his railroad's experience with the design (p. 366): "We find them a very good suburban engine, and I believe the best I ever saw."

Peck noted an issue or two: "The only thing about them is the maintenance. We have had to remove the tanks to replace one stay bolt, but if we had a shop to take care of them I think that would be a very small item. We found at first we could not keep the trailing wheels cool, and that annoyed us very much. I wrote to almost every one who have used this type of engine, and found that most of them had had the same experience in regard to the trailers. The assistant superintendent of the Rogers Locomotive Works came here and examined them, and furnished a brass of special composition, since which time we have had no trouble. The babbitt in the bearing is made of a compound of seventy-five per cent of soft lead, ten per cent of hard lead, five per cent of antimony and ten of tin."

This response from Rogers did the trick: "Since that time we have had no trouble and they have been running now for three months."

Another problem was the long time it took to fill the water tanks. After putting a water space under the cab and not seeing the results the C&WI had hoped for, "we cut long holes in the side of the tank and we filled them to the highest part of the tank, and in that way we don't experience trouble. Before, it took entirely too long to fill them. It had to go through this small tank and there was no pressure to bring the water up."

As to their deportment in service: "They don't slip any, and handle trains nicely, and they are as nice riding engines as a man ever rode on. Our engineers all like them. They ride as nice as any coach. The service is entirely satisfactory and the only question is the maintenance, but we have not had them long enough to make any statement about that."

His final comment shows that not all railroads were created equal: "If we had a shop of modern appliances, such as overhead cranes and so on, I don't think we would have much trouble."

The R&LE offered a remarkably involved image for the type of footholds in the locomotive's water tank: The two pocket steps just above the regular hanging steps for the cab door ...are something like the niches for hands and feet which an Alpine climber would cut out of an ice wall when on a long, hard climb." Exactly the picture that sprang to mind when viewing the halftone.

Principal Dimensions by Steve Llanso of Sweat House Media

Locobase ID472
RailroadChicago & Western Indiana
Number in Class3
Road Numbers100-102 /2-4/202-204
Number Built3
Valve GearStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)14 / 4.27
Engine Wheelbase (ft / m)31.17 / 9.50
Ratio of driving wheelbase to overall engine wheelbase 0.45
Overall Wheelbase (engine & tender) (ft / m)31.17 / 9.50
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)130,000 / 58,967
Engine Weight (lbs / kg)190,000 / 86,183
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)190,000
Tender Water Capacity (gals / ML)3500 / 13.26
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)5 / 5
Minimum weight of rail (calculated) (lb/yd / kg/m)72 / 36
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)63 / 1600
Boiler Pressure (psi / kPa)200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)18" x 26" / 457x660
Tractive Effort (lbs / kg)22,731 / 10310.62
Factor of Adhesion (Weight on Drivers/Tractive Effort) 5.72
Heating Ability
Tubes (number - dia) (in / mm)249 - 2" / 51
Flues (number - dia) (in / mm)
Flue/Tube length (ft / m)13 / 3.96
Firebox Area (sq ft / m2)146.50 / 13.61
Grate Area (sq ft / m2)46.80 / 4.35
Evaporative Heating Surface (sq ft / m2)1841 / 171.03
Superheating Surface (sq ft / m2)
Combined Heating Surface (sq ft / m2)1841 / 171.03
Evaporative Heating Surface/Cylinder Volume240.34
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation9360
Same as above plus superheater percentage9360
Same as above but substitute firebox area for grate area29,300
Power L17055
Power MT358.93

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Wes Barris