Texas Mexican / Texas Midland 4-6-0 "Ten-wheeler" Locomotives of the USA

Class Details by Steve Llanso of Sweat House Media

Class 1 (Locobase 14964)

Data from DeGolyer, Vol 65, pp. 284. See also the Handbook of Texas entry George C. Werner, "TEXAS MEXICAN RAILWAY," Handbook of Texas Online (http://www.tshaonline.org/handbook/online/articles/eqt21), accessed February 24, 2013. Published by the Texas State Historical Association.. Works numbers were 52921 in January 1920, 55732 in November 1922.

The TM was chartered in 1875 as the 3-foot-gauge (914 mm) Corpus Christi, San Diego & Rio Grande and completed 52 miles (84 km) to San Diego, Texas by 1879 and another 110 miles (177 km) to Laredo by September 1881. At that point, the owners sold the line to the Mexican National Railway then being built between Nuevo Laredo and Mexico City.

After seven years under the MNR's mantle, the TM regained its independence. It converted to standard gauge in 1902 and absorbed the Texas Mexican Northern in 1906.

These modestly scaled oil-burning Ten-wheelers were the passenger power on the TM (at least they were described as passenger engines by Baldwin. Superheated as they were, they used 9 1/2" (241 mm) piston valves to supply steam to the cylinders. A note entered on the 1922 spec instructed the painters that "Flat colors will not stand in this hot climate, nor will white lead primers." So they used instead "one coat of Celox liquid primer, rough stuffed, then two coats of Valspar black, lettered, then two coats of Valentine"s Valspar varnish."

The 1 was delivered to the TM, sometime later operated as a logging engine for the R Gonzalez and Brother operation, and returned to the TM. The 2 arrived almost three years later and weighed slightly more (1,500 lb/680 kg more on the drivers, 2,000 lb/907 kg).

Once the TM dieselized in 1939 (the earliest railroad to go all diesel in the US, or possibly anywhere), the 1 found a home on the Frost Lumber Company's Arkansas & Louisiana Missouri timber railway headquartered at Crossett, Ark. It was scrapped decades later in December 1961.

Class 11 (Locobase 14967)

Data from DeGolyer, Volume 65, pp. 292. Works numbers were 54815, 54835 in May 1921.

Locobase 14964 shows the two "passenger" engines delivered to the TM in 1920 and 1922. (We know they hauled people because Baldwin's spec said specifically that the service was "passenger".) A year after the 1 arrived, the 11 and 12 followed with longer, deeper fireboxes and more tubes and flues. Most ratios remained the same, however, and these were also oil-burning Ten-wheelers.

Although they rolled on 58" drivers (i.e. 2" taller than the 1's), the 'teen engines were classed as freighters. Their adhesive wheelbases stretched 33" (838 mm) further and the engine wheelbase measured 35" (889 mm) greater.

The 12 was sold to the Reader Railroad, but kept its road number. The 11 was off the roster by 1947.

Class 114 (Locobase 11133)

Data from Schenectady Locomotive Works, Illustrated Catalogue of Simple and Compound Locomotives (Philadelphia: J B Lippincott, 1897), pp. 104-105. See also the Handbook of Texas entry at http://www.tshaonline.org/handbook/online/articles/TT/eqt22.html, last accessed 24 January 2010.

The Midland Route was chartered on 1 December 1892 to run between Garrett and Greenville, but already included 51 miles of line between Garrett and Roberts built originally by the Houston & Texas Central. The railroad eventually reached the H & TC's original goal at Paris.

Class 14 (Locobase 14968)

Data from DeGolyer, Volume 65, pp. 296+ and Volume 76, pp 420+. Works numbers were 57638 in February 1924, 58058 in October, and 59530 in September 1926.

Locobase 14964 shows the two oil-burning Ten-wheelers that introduced a slightly bigger boiler and firebox to the TexMex compared to the 1 of 1920. In 1924, Baldwin produced more in this line in which weight distribution changed and power increased.

Tweaks to the power dimensions involved a 10 psi (0.7 bar) increase in boiler pressure and a 2" (50.8 mm) drop in driver diameter. The engines also registered a significant weight shift off the front bogie truck to the drivers. Piston valve diameter grew 1/2" to 10" (254 mm) Engine weight grew by only 1,500 lb (680 kg), but adhesion weight rose by more than six short tons to 123,500 lb (56,018 kg). Also, the front pair of drivers had only 53" (1,346 mm) between the insides of the tires to allow 1" (25.4 mm) of track play in either direction.

Gene Connelly's magisterial work on Baldwin production couldn't provide much data on this class's later career after the TM went all-diesel in 1939. Later information from Al Weber's creation of data cards for each works number showed that the 14 was scrapped in 1947, 15 went to Crossett, Ark in 1947 to run on the Arkansas & Louisiana Missouri. 16 was off the Tex-Mex roster by 1947.

Specifications by Steve Llanso of Sweat House Media
Locobase ID14964 14967 11133 14968
RailroadTexas MexicanTexas MexicanTexas MidlandTexas Mexican
Number in Class2223
Road Numbers1-211-1211414-16
Number Built2223
Valve GearWalschaertWalschaertStephensonWalschaert
Locomotive Length and Weight
Driver Wheelbase11.33'14'13.83'14'
Engine Wheelbase21.83'24.75'24'24.75'
Ratio of driving wheelbase to overall engine wheebase 0.52 0.57 0.58 0.57
Overall Wheelbase (engine & tender)51.27'53.29'46'53.29'
Axle Loading (Maximum Weight per Axle)
Weight on Drivers105500 lbs111000 lbs76500 lbs123500 lbs
Engine Weight137500 lbs156500 lbs104000 lbs158000 lbs
Tender Light Weight109000 lbs132500 lbs132500 lbs
Total Engine and Tender Weight246500 lbs289000 lbs290500 lbs
Tender Water Capacity5000 gals6000 gals3500 gals6000 gals
Tender Fuel Capacity (oil/coal)2000 gals3000 gals gals3000 gals
Minimum weight of rail (calculated)59 lb/yard62 lb/yard43 lb/yard69 lb/yard
Geometry Relating to Tractive Effort
Driver Diameter56"58"56"56"
Boiler Pressure180 psi180 psi160 psi190 psi
Cylinders (dia x stroke)19" x 26"20" x 26"18" x 24"20" x 26"
Tractive Effort25644 lbs27434 lbs18885 lbs29993 lbs
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.11 4.05 4.05 4.12
Heating Ability
Firebox Area138 sq. ft162 sq. ft133.28 sq. ft162 sq. ft
Grate Area28.30 sq. ft28.50 sq. ft17.23 sq. ft28.50 sq. ft
Evaporative Heating Surface1574 sq. ft1714 sq. ft1556 sq. ft1714 sq. ft
Superheating Surface332 sq. ft363 sq. ft363 sq. ft
Combined Heating Surface1906 sq. ft2077 sq. ft1556 sq. ft2077 sq. ft
Evaporative Heating Surface/Cylinder Volume184.48181.30220.13181.30
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation5094513027575415
Same as above plus superheater percentage5960600227576336
Same as above but substitute firebox area for grate area29063341172132536013
Power L11034110658469510863
Power MT648.28635.05405.91581.75

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