Acquired in 1901 with the usual fanfare, this class pitted the Vauclain compound system against the demands of "passenger service on grades of 3 and 4 per cent. and curves of 16 degrees in the mountains of Colorado. These conditions required unusual tractive power and involved a large weight on driving wheels. M.. Vauclain, of the Baldwin Locomotive Works, in explaining the reason for the inclination of the cylinders of this engine, said that the officers of the road wanted the cylinders sufficiently high to clear the 'scenery' of the Rocky Mountains, which is 'so unstable that it is likely to be found alongside the railroad tracks'".
They cannot be described as "flyers", but the locomotives hauled four cars --a combination mail and smoker, two chair cars, and a sleeper weighing a combined 150 tons--over the Manitou-Cascade section that featured steep grades and six tunnels in a 3.4 mile (5.5 km) stretch. A"tourist sleeper" joined the train on weekends and some trains of six cars of 230 tons
this set of Vauclain compounds soon proved as unsuitable to the CM's requirements as most other North American railroads found compounds to be. They were rebuilt in 1908 with two simple-expansion 21" x 30" cylinders. The financially strapped CM finally closed in August 1918.
The class was superheated, the effect of which is shown in Locobase 16006.
Locomotive reseller W A Zelnicker bought all five in 1919 and sold them in March 1920 to the Louisiana & Arkansas, taking numbers 429, 425-428.
Works numbers were 32124-32127, 32151,32152 in November 1907.
After the CM closed in 1919, this class went into storage until 1921, when it was sold to the Central Mexicano as their 1-6. The Nacional de Mexico nationalized the CM and placed the sextet in its G-35 class, giving them road numbers 785-790 and, after 1930, 1434-1439. See Locobase 11977 for the G-35, which used a modified boiler and firebox, possibly as a result of a conversion to oil-firing
Locobase 7698 shows the Schenectady engines supplied to the Midland Terminal (a subsidiary of the CM) and these appear to be duplicates supplied by Baldwin a couple of years later.
After 25 years, the CM was abandoned in 1919. Two of the engines -- 50 and 53 -- went to the Midland Terminal. The other were sold to the locomotive rebuilder/reseller Birmingham Rail & Locomotive, which induced the Boyne City, Gaylord & Alpena to buy the trio in January 1920. They were renumbered 5-7. (See Locobase 11484 for a discussion of the railroad.)
The direct heating surface is an estimate based on the Schenectady engines.
|Principal Dimensions by Steve Llanso of Sweat House Media|
|Railroad||Colorado Midland||Colorado Midland||Colorado Midland|
|Number in Class||5||6||5|
|Builder||Burnham, Williams & Co||Burnham, Williams & Co||Burnham, Williams & Co|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||15.75 / 4.80||14.50 / 4.42||14.33 / 4.37|
|Engine Wheelbase (ft / m)||24.33 / 7.42||23 / 7.01||22.25 / 6.78|
|Ratio of driving wheelbase to overall engine wheebase||0.65||0.63||0.64|
|Overall Wheelbase (engine & tender) (ft / m)|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)|
|Weight on Drivers (lbs / kg)||160,000 / 72,575||175,000 / 79,379||133,000 / 60,328|
|Engine Weight (lbs / kg)||180,000 / 81,647||193,000 / 87,543||150,000 / 68,039|
|Tender Loaded Weight (lbs / kg)||120,000 / 54,431||130,000 / 58,967||85,000 / 38,555|
|Total Engine and Tender Weight (lbs / kg)||300,000 / 136,078||323,000 / 146,510||235,000 / 106,594|
|Tender Water Capacity (gals / ML)||6000 / 22.73||6500 / 24.62||4000 / 15.15|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||12 / 10.90||10 / 9.10|
|Minimum weight of rail (calculated) (lb/yd / kg/m)||67 / 33.50||73 / 36.50||55 / 27.50|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||60 / 1524||52 / 1321||52 / 1321|
|Boiler Pressure (psi / kPa)||200 / 13.80||200 / 13.80||180 / 12.40|
|High Pressure Cylinders (dia x stroke) (in / mm)||17" x 30" / 432x762||22" x 28" / 559x711||21" x 26" / 533x660|
|Low Pressure Cylinders (dia x stroke) (in / mm)||25" x 30" / 635x762|
|Tractive Effort (lbs / kg)||33,595 / 15238.45||44,305 / 20096.43||33,737 / 15302.86|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.76||3.95||3.94|
|Firebox Area (sq ft / m2)||172.20 / 16||158 / 14.68||162.30 / 15.08|
|Grate Area (sq ft / m2)||35 / 3.25||49.50 / 4.60||31.70 / 2.95|
|Evaporative Heating Surface (sq ft / m2)||2626 / 244.05||3324 / 308.92||2125 / 197.42|
|Superheating Surface (sq ft / m2)|
|Combined Heating Surface (sq ft / m2)||2626 / 244.05||3324 / 308.92||2125 / 197.42|
|Evaporative Heating Surface/Cylinder Volume||333.20||269.82||203.88|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||7000||9900||5706|
|Same as above plus superheater percentage||7000||9900||5706|
|Same as above but substitute firebox area for grate area||34,440||31,600||29,214|