New Orleans Pacific / Texas & Pacific 4-6-0 "Ten-Wheeler" Locomotives in the USA


Class Details by Steve Llanso of Sweat House Media

Class 104/D-2 (Locobase 16641)

Data from T&P 1 - 1922 and T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 500

500 in May 1881, 501-504 in June.

Locobase 8497 shows the twenty locomotives delivered directly to the Texas & Pacific in 1800-1881. But lesser-known NOP was organized in Louisiana in 1875 to link Shreveport to New Orleans)

The NOP ordered this set to piggyback on the T&P batch. It's a technicality, perhaps, but the engines were built as NOPs a month or less before the T&P bought the New Orleans Pacific on 1 June 1881. The five NOPs joined the 20 T&Ps to complete the D-2 class.

NB: An opportunity to plunge deep into the weeds of railroad ownership and grants presents itself to the reader of US Attorney General Benjamin Harris Brewster's 1882 opinion of the relative merits in Thomas Donaldson, The Public Domain-Its History (Washington, DC: US Government Printing Office, 1884), pp. 856-860; and "New Orleans, Baton Rouge and Vicksburg Railway", Copp's Landowner (1 June 1883), pp 75-77 to learn the intricate history of the dispute.

Eventually it reached the US Supreme Court as New Orleans Pacific Ry. Co. v. United States, 124 U.S. 124 (1888). Justice Blatchford's opinion begins at [], last accessed 6 July 2023. Locobase concludes the petitioner (New Orleand Pacific) failed to satisfy conditions specified in several statutes and therefore could not claim a "patent".


Class 224 (Locobase 16172)

Data from DeGolyer, Volume 18, p. 26. Works numbers were 12821, 12825-12826, 12832, 12851.

This sextet of Ten-wheelers duplicated the specifications prepared in the same year for the Chicago, Rock Island & Pacific's set of 30 4-6-0s. The only significant difference was the adoption of 62" drivers, which suited the type for mixed-traffic work.

229 (Works number 12387)was delivered as a Vauclain compound with 13" HP and 22" LP cylinders. It was rebuilt as a simple-expansion engine in 1895 after a rear end collision.

All six would get new boilers and fireboxes; see Locobase 8502.


Class D--11 (Locobase 13936)

Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University, Volume 41, p. 218. Works numbers were 38037-38046 in June 1912.

The last of the T & P's favorite wheel arrangement, the D-11 class reflected the older design philosophy that used saturated boilers and slide valves. The specs show a substantial correction in the estimated grate area as an 8 June 1912 note crossed out the orginal figure of 56.8 sq ft and substituted the 34.1 sq ft shown in the data.

Locobase 8508 shows the result when the T & P superheated the class beginning in 1916.


Class D-10 (Locobase 5696)

Data from June 1908 table in American Engineer and Railroad Journal. Works numbers were 44476-44515 in October 1907.

These dual-service Tenwheelers were the second most numerous single class on the T&P. They were relatively large for the arrangement at the time and obviously proved very useful. So the entire class went through a modification program that included superheating the locomotive's boilers; see Locobase 8507.


Class D-10-s (Locobase 8507)

Data from T&P 1 - 1922 and T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

The T & P took delivery of these definitive Ten-wheelers in their saturated-boiler form in 1907 (Locobase 5696).

Unlike many of the other 4-6-0 classes on the road, however, the D-10s were big enough to be worth upgrading with superheat and were already equipped with Walschaert gear and 14" piston valves. Beginning in 1915, most of the class went through the upgrade. During the process, the entire power system was enlarged. The grate grew slightly by being widened 4" (102 mm), the cylinders were enlarged by 2"(50.8 mm) in diameter, and the total heating surface area also increased (a rarity in such makeovers). Such enlargements and additions added almost 6 tons to the locomotive's operating weight. Valve gear was either Southern (361-380) or Walschaert (381-400).

One edition of the locomotive diagram states that the heating surface of the superheater was stated to be 772 sq ft as of 5-22-29. Locobase suspects this was "equivalent heating surface" derived by multiplying each actual square foot of superheater area by 1.5 to indicate its greater contribution to making quality steam.

Still later some engines received feedwater heaters and even larger tenders with 10,000-US gallons (38,750 litres) water and 4,005 gallon (15,159 litre) oil capacities. Seven were fitted with thermic syphons in the mid 1930s which added 55 sq ft (5.11 sq m) to the firebox heating surface, but only 2 sq ft to the evaporative heating surface area.


Class D-11-s (Locobase 8508)

Data from T&P 1 - 1922 and T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Locobase 13936 shows the D-11 class as it was delivered from Eddystone. Beginning in December 1915 with 413, the T&P converted the class to oil-firing and superheated them as well. Some were fitted with Universal valve chests, a piston-valve conversion kit installed in the original casting, while others received 11" piston valve cylinders. The last of the class was superheated by May 1917 while the last oil burner was installed in 413 in February 1920.

In their more powerful incarnations, the class served through World War II. 412 was first to the scrapyard, being retired in April 1947 and scrapped three months later. The last to go to the ferro-knacker was 419, which was scrapped in November 1949.


Class D-2 (Locobase 8497)

Data from T&P 1 - 1922 and T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 408-409 in June 1880, 410-411 in July, 414-417 in August, 449 in September, 450 in October., 468-472 in February 1881, 473-477 in April.

The diagram from 1922 showed a classic early-80s profile with the dome located over the firebox, the firebox between the drivers and driving axles, the first two driving axles closely spaced, and a tall slender stack. Locobase 16641 describes the history of the last five, originally ordered by the New Orleans Pacific Railway.


Class D-3 (Locobase 8498)

Data from T&P 1 - 1922 and T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 1083-1085 (road numbers 166-168) in December 1885, 1094-1095 (road 161-162) in February 1886, and

1131-1133 (road 163-165) in July.

These were typical mid-1880s freight haulers. The first three locomotives originally came off the production line headed for the Burlington, Cedar Rapids & Northern as their 101-103. Apparently the BCR&N couldn't pay for the engines, so Brooks repossessed the trio and sold them to the T&P.

163 had 52" (1,321 mm) drivers and a tractive effort of 19,400 lb (8,800 kg or 86.30 kN). After a long career with the T&P, the 163 entered a second career in September 1925 when it was bought by the Jefferson & Northwestern Railway.

Originally built on the 3' (914 mm) gauge serving the Jefferson Lumber Company. The J&NW had built 22.5 miles when it converted to standard gauge in 1908. Its main line ran from Jefferson, Texas 48.9 miles (78.8 km) to Naples.

In 1933, Clark & Boice closed its sawmill in Jefferson, which almost immediately led to the abandonment of the 29 miles (46.7 km) between Linden and Naples. Although the railway was reorganized as the J&NW Railroad, its continuing losses caused the rest of the line to close in 1941.


Class D-4 (Locobase 8499)

Data from T&P 1 - 1922 and T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Very similar to the 1886 Brooks Ten-wheelers shown in Locobase 8498, these had longer boiler tubes, a slightly smaller grate, and, like the D-3, two different driver diameters. Some locomotives had the 57" drivers shown, others a set of 51" wheels.


Class D-5 (Locobase 8500)

Data from T&P 1 - 1922 and T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 15, p. 109, and volume 19, p. l3. Works numbers were

1889

July 10081-10082, 10084-10088, 10091; August 10199, 10202, 10206, 10208-10212, 10215-10220; September 10222, 10225, 10230

1890

November 11346-11347, 11349-11351, 11354, 11359-11361, 11381

1892

July 12821, 12825-12826, 12832, 12851 in July 1892.

Very similar to the 1886 Brooks Ten-wheelers shown in Locobase 8498, these had longer boiler tubes, a slightly smaller grate, and, like the D-3, two different driver diameters. The 1889-1890 locomotives were delivered with 51" drivers. The 1892 batch had the 57" drivers shown. All of the earlier engines later rolled on 57" wheels.

Most of the class served all their days on the T&P. The 203 was sold to the Eastland, Wichita Falls & Gulf and the 223 went to the Pecos Valley. Cement manufacturer Gifford Hill & Co in San Antonio bought 204, 209, 217, 220. 217 later went on to the Evangeline Railway and the 220 wound up with SouthWest Construction.


Class D-6 (Locobase 8502)

Data from T&P 1 - 1922 and T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange.

Some time after the original delivery of the six Ten-wheelers from Baldwin in 1892, the T&P installed new fireboxes and boilers in the class. The boiler had sixteen fewer tubes, but the firebox grew and was converted to oil burning. Although the diagram doesn't indicate as much, the increased firebox area probably came from arch tubes. Another change was in the larger tender, which held more water and oil instead of coal.

224 retired first in November 1914, possibly because of a defective boiler because when 227 retired in June 1916, its boiler went to the 224. While the 227 fell under the ferro-knacker's torch a month later, the 224 apparently reentered service. Nine years later, Evangeline Gravel Company in Alexandria, La bought the 224.

228 was retired in September 1916 and scrapped in March 1918. 226 and 229 were both retired in February 1923 and scrapped in the same year. 225 was withdrawn in December 1923 and sold to Ruston Foundry (also in Alexandria, La) in February 1924.


Class D-7 (Locobase 8503)

Data from T&P 1 - 1922 and T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. See also DeGolyer, Volume 20, p. 108; and "Some Recent Rogers Locomotives", Railroad Gazette, Volume XXX [30], No 48 (3 December 1898), p.857.

Just at the end of the century, the T&P ordered Ten-wheelers of the same design from Baldwin and Paterson, NJ-based Rogers and Cooke works. Baldwin supplied four in 1898 (works numbers 15622, 15265, 15627-15628 in December) , Rogers two in 1898 (works numbers 5327-5328 and three in 1900 (5618-5620), and Cooke delivered eight (works numbers 2695-2702) in 1901.

These were more definitely intended for passenger working. Baldwin's specs estimated 108,000 lb (48,988 kg) on the drivers, 140,000 lb (63,503 kg) as engine weight. The considerable weight growth could have come from later updates, a Baldwin miscalculation, or an engine from either Rogers or Cooke. Rogers' first two were credited in RG's 1898 report with 115,000 lb (52,164 kg) on the drivers and 156,500 lb (70,987 kg) overall; the front truck's load of 41,500 lb (18,824 kg) seems awfully high.

The engines were originally delivered with Stephenson (Williams Howe) link motion. By the time the diagram in the 1922 book was prepared, 239-240, 242-244, 267-269, and 271 had been refitted with Walschaert's outside constant-lead radial valve gear.. The Rogers engines profiled in RG had fireboxes with four water tubes supporting the firebrick arch.

More than half were scrapped in the 1920s 241, 266, 272, 273 in January 1924, and 240, 242, 243, 268, 270 in January 1926) after relatively short service lives. The rest were withdrawn in the early 30s 271 in December 1931 and 244 in November 1931, two in January 1933, the remainder later in the decade).


Class D-8 (Locobase 8504)

Data from T&P 1 - 1922 and T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange; and "Rogers Locomotives for the Texas & Pacific", Railway Age, Volume XXVI [26], No 11 (16 September 1898), p. 659.(Thanks to Chris Hohl for his 25 July 2023 email noting the smaller drivers on delivery, valve gear ID, and the smaller fuel capacities in the oriiginal tender.) Works numbers were 5282-5285 in July 1898, 5286-5291 in August.

As Rogers delivered the passenger D-7s (Locobase 8503), the builder also produced these smaller mixed-traffic engines, rolling them out on 57" (1,448 mm) drivers. They trailed tenders holding 4,500 US gallons (17,033 litres) of water and 6 tons (5.45 metric tons) of coal.

As railroad journals often did in that era, Railway Age listed additional equipment that can illustrate the industry that supported each locomotive: The equipment includes

Johns asbestos boiler covering,

Gollmar bellringer

Westinghouse-American brakes,

interchangeable brake beams,

American Steel Foundry company's couplers.

Pyle National electric headlights,

Monitor injectors,

Nathan lubricators,

phosphor-bronze journal bearings,

Coale safety valves,

Houston sanding device,

Pickering springs,

Ashcroft steam gauges,

Otis steel in boiler and firebox,

Krupp, Midvale and Standard tires,

cast-steel driving wheel centers.

At some point, the T&P fitted 6" (152 mm) taller drivers and many exchanged their inside link valve motion for Walschaert constant-lead radial valve gear. Although most were scrapped after 25-35 years of service, a few were retained into the late 1930s.

248 was sold to the Saginaw & Manistee Lumber Company's W E O Railroad in February 1943. After several years on that Arizona road, the engine met the scrap dealer. 253 went to the Pecos Valley Southern in October 1947 as their 7; it was gone from the PVS by 1949.


Class D-9 (Locobase 8505)

Data from T&P 1 - 1922, Military Railway Service US Locomotives Diagrams, and T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for his 18 March 2016 email for information on the varying valve gear and the Alco-Rogers locomotive batch and for a later email correcting the original design's Locobase number. Thanks also to Steve Low for his 9 December 2017 email providing details on the US Army's use of seven D-9s of the class in World War Two.)

The biggest single class of Ten-wheelers on the T&P came from the two Paterson firms -- Rogers and Cooke -- that were absorbed into the American Locomotive Company in the early 1900s. Rogers began the deliveries with 7 in 1900. Works numbers were 5590-5591, 5593 in July 1900; 5594-5595, 5597-5598 in August. Cooke followed with 42 in 1901-1902, then each delivered engines in 1903. Works numbers were 2678-2681 in July 1901; 2682-2694 in August.

A year later and following Cooke's absorption, the next batch had works numbers 25951-25965 in July 1902; 26133-26141 in November, and 28480-28494 in May 1903. Shortly after Rogers merged with Alco, the builder finished the class with works numbers 41488-41497 in December 1906.

The T&P updated some of this class with valve chests holding piston valves. The original Stephenson link motion was replaced by outside radial valve gear; see Locobase 8506.

As these were mixed-traffic locomotives, they were more flexibly used once passenger trains were coupled to later, faster designs. Most had been scrapped by World War Two and four--302, 308, 327, 354--were cancelled 17 August 1937and sold to the Paris & Mt Pleasant.

Steve Low's email cited innformation from page 25 of R Tourret, United States Army Transportation Locomotives (Abingdon, UK: Tourret Publishing, 1977). His summary of Tourret's account says the following:

"The USATC used seven ex Texas & Pacific T&P Class D-9 locomotives for its Camp Claiborne La training establishment, which was established in 1941.

Builders numbers were as follows:

USATC #1 & #2 were Cooke 2688/90 of 1901.

USATC #3-#5 were Alco-Cooke 25960 and 26132/40 of 1902

USATC #6 was Alco-Cooke 28489 of 1902

USATC #7 was Alco-Rogers 41496 of 1906.

These were T&P 285/7, 301/10/4/33/57 respectively.

The septet was "overhauled and painted olive green in the T&P Marshall shops before handover. USATC #1 arrived at Camp Claiborne in December 1941and #2-#7 in January 1942. They were delivered with 'US Corps of Engineers' painted on the sand domes but later they became USATC property. They were sold or scrapped in 1947."

316 followed in August 1949 and would be put on display in Abilene in 1955 after its retrement.

Many more went in the war's early years, but a few lasted until the late 1940s.


Class D-9 1/2 (Locobase 8506)

Data from T&P 1 - 1922 and T&P 1 - 1950ca Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Chris Hohl's 18 March 2016 email query prompted a clarification in this entry.) Two of the class were built from scratch in 1906 by the T&P at their own shops.

The others were all conversions. The designation "9 1/2" referred to D-9 locomotives (Locobase 8505) fitted with 11" (279 mm) piston valves in modified valve chests actuated by outside radial valve gear. The T&P shops used two different "economy" steam chests, the "Universal" and the "Simplified". Page 916 of the 1916 Locomotive Cyclopedia gives details on the Universal installation, but Locobase is still searching for information on the "Simplified." Engines equipped with the Universal from 16 Oct 1916 to 31 May 1919 were, in order of their conversion, 332, 277, 360, 326, 334, 312, and 282. In that same period (30 Oct 1916 to 31 May 1919), four--359, 274, 358, 276--received the Simplified.

They also received 4" (102 mm) taller drivers for more speed. The key addition was a superheater at the cost of less than 60 sq ft (5.74 sq m) in total heating surface area.

Principal Dimensions by Steve Llanso of Sweat House Media

Class104/D-2224D--11D-10D-10-s
Locobase ID16641 16172 13936 5696 8507
RailroadNew Orleans Pacific (T&P)Texas & Pacific (T&P)Texas & Pacific (T&P)Texas & Pacific (T&P)Texas & Pacific (T&P)
CountryUSAUSAUSAUSAUSA
Whyte4-6-04-6-04-6-04-6-04-6-0
Number in Class55104036
Road Numbers 104-108224-228411-420361-400361-400
GaugeStdStdStdStdStd
Number Built551040
BuilderPittsburghBurnham, Williams & CoBaldwinAlco-BrooksTexas & Pacific
Year18801892191219071915
Valve GearStephensonStephensonWalschaertvariousvarious
Locomotive Length and Weight
Driver Wheelbase (ft / m)12.83 / 3.9111.50 / 3.5114.83 / 4.5214.83 / 4.5214.83 / 4.52
Engine Wheelbase (ft / m)24.83 / 7.5722.25 / 6.7825.83 / 7.8726.33 / 8.0325.50 / 7.77
Ratio of driving wheelbase to overall engine wheelbase 0.52 0.52 0.57 0.56 0.58
Overall Wheelbase (engine & tender) (ft / m)49.56 / 15.1148.37 / 14.7459.92 / 18.2655.77 / 1761.98 / 18.89
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)66,500 / 30,16490,000 / 40,823150,000 / 68,039165,000 / 74,843163,000 / 73,936
Engine Weight (lbs / kg)91,000 / 41,277115,000 / 52,163192,000 / 87,090197,000 / 89,358211,660 / 96,007
Tender Loaded Weight (lbs / kg)63,500 / 28,80387,200 / 39,553130,000 / 58,967132,867 / 60,268181,884 / 82,501
Total Engine and Tender Weight (lbs / kg)154,500 / 70,080202,200 / 91,716322,000 / 146,057329,867 / 149,626393,544 / 178,508
Tender Water Capacity (gals / ML)4000 / 15.153600 / 13.646500 / 24.626500 / 24.629400 / 35.61
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)1500 / 56789 / 812 / 113115 / 11,790
Minimum weight of rail (calculated) (lb/yd / kg/m)37 / 18.5050 / 2583 / 41.5092 / 4691 / 45.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)57 / 144862 / 157567 / 170263 / 160063 / 1600
Boiler Pressure (psi / kPa)145 / 10165 / 11.40200 / 13.80210 / 14.50185 / 12.80
High Pressure Cylinders (dia x stroke) (in / mm)17" x 24" / 432x61020" x 24" / 508x61021" x 28" / 533x71122" x 28" / 559x71124" x 28" / 610x711
Tractive Effort (lbs / kg)14,998 / 6802.9921,716 / 9850.2231,331 / 14211.5238,397 / 17416.6140,256 / 18259.84
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.43 4.14 4.79 4.30 4.05
Heating Ability
Tubes (number - dia) (in / mm)159 - 2" / 51254 - 2" / 51315 - 2" / 51326 - 2" / 51198 - 2" / 51
Flues (number - dia) (in / mm)28 - 5.375" / 137
Flue/Tube length (ft / m)11.83 / 3.6113.25 / 4.0415 / 4.5716 / 4.8816 / 4.88
Firebox Area (sq ft / m2)110 / 10.22128.80 / 11.97211 / 19.60200 / 18.59200 / 18.58
Grate Area (sq ft / m2)16 / 1.4923.50 / 2.1834.10 / 3.1746.30 / 4.3048.20 / 4.48
Evaporative Heating Surface (sq ft / m2)1190 / 110.591893 / 175.862671 / 248.142931 / 272.402490 / 231.41
Superheating Surface (sq ft / m2)525 / 48.79
Combined Heating Surface (sq ft / m2)1190 / 110.591893 / 175.862671 / 248.142931 / 272.403015 / 280.20
Evaporative Heating Surface/Cylinder Volume188.59216.84238.06237.91169.85
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation23203878682097238917
Same as above plus superheater percentage232038786820972310,433
Same as above but substitute firebox area for grate area15,95021,25242,20042,00043,290
Power L1379849557417703610,885
Power MT377.74364.13327.03282.03441.67

Principal Dimensions by Steve Llanso of Sweat House Media

ClassD-11-sD-2D-3D-4D-5
Locobase ID8508 8497 8498 8499 8500
RailroadTexas & Pacific (T&P)Texas & Pacific (T&P)Texas & Pacific (T&P)Texas & Pacific (T&P)Texas & Pacific (T&P)
CountryUSAUSAUSAUSAUSA
Whyte4-6-04-6-04-6-04-6-04-6-0
Number in Class102081344
Road Numbers411-42071-92/573-591 104-108161-168170-182189-223, 230-238
GaugeStdStdStdStdStd
Number Built2081344
BuilderT&PPittsburghBrooksNew YorkBurnham, Parry, Williams & Co
Year19151880188618871889
Valve GearWalschaertStephensonStephensonStephensonStephenson
Locomotive Length and Weight
Driver Wheelbase (ft / m)14.83 / 4.5212.83 / 3.9113.75 / 4.1913.75 / 4.1914 / 4.27
Engine Wheelbase (ft / m)25.83 / 7.8724.83 / 7.5724.75 / 7.5424.75 / 7.5424.72 / 7.53
Ratio of driving wheelbase to overall engine wheelbase 0.57 0.52 0.56 0.56 0.57
Overall Wheelbase (engine & tender) (ft / m)59.85 / 18.2449.56 / 15.1149.58 / 15.1149.40 / 15.0649.40 / 15.06
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)152,370 / 69,11466,500 / 30,16472,000 / 32,65973,000 / 33,11290,500 / 41,050
Engine Weight (lbs / kg)196,800 / 89,26791,000 / 41,27794,000 / 42,63897,000 / 43,999121,000 / 54,885
Tender Loaded Weight (lbs / kg)145,200 / 65,86263,500 / 28,80379,000 / 35,83479,000 / 35,83497,372 / 44,167
Total Engine and Tender Weight (lbs / kg)342,000 / 155,129154,500 / 70,080173,000 / 78,472176,000 / 79,833218,372 / 99,052
Tender Water Capacity (gals / ML)6500 / 24.624000 / 15.154500 / 17.054500 / 17.055000 / 18.94
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)3022 / 11,4381500 / 56782000 / 75702000 / 75702571 / 9731
Minimum weight of rail (calculated) (lb/yd / kg/m)85 / 42.5037 / 18.5040 / 2041 / 20.5050 / 25
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)67 / 170257 / 144857 / 144857 / 144857 / 1448
Boiler Pressure (psi / kPa)200 / 13.80145 / 10150 / 10.30150 / 10.30175 / 12.10
High Pressure Cylinders (dia x stroke) (in / mm)21" x 28" / 533x71117" x 24" / 432x61018" x 24" / 457x61018" x 24" / 457x61019" x 24" / 483x610
Tractive Effort (lbs / kg)31,331 / 14211.5214,998 / 6802.9917,394 / 7889.8017,394 / 7889.8022,610 / 10255.74
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.86 4.43 4.14 4.20 4.00
Heating Ability
Tubes (number - dia) (in / mm)190 - 2" / 51159 - 2" / 51184 - 2" / 51184 - 2" / 51230 - 2" / 51
Flues (number - dia) (in / mm)26 - 5.375" / 137
Flue/Tube length (ft / m)15 / 4.5711.83 / 3.6113.14 / 4.0113.67 / 4.1713.17 / 4.01
Firebox Area (sq ft / m2)216 / 20.07110 / 10.22110 / 10.22120 / 11.15145 / 13.47
Grate Area (sq ft / m2)35 / 3.2516 / 1.4917 / 1.5816.50 / 1.5317 / 1.58
Evaporative Heating Surface (sq ft / m2)2257 / 209.761190 / 110.591250 / 116.171385 / 128.721745 / 162.17
Superheating Surface (sq ft / m2)456 / 42.38
Combined Heating Surface (sq ft / m2)2713 / 252.141190 / 110.591250 / 116.171385 / 128.721745 / 162.17
Evaporative Heating Surface/Cylinder Volume201.16188.59176.80195.90221.45
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation70002320255024752975
Same as above plus superheater percentage81902320255024752975
Same as above but substitute firebox area for grate area50,54415,95016,50018,00025,375
Power L114,8113798362840015211
Power MT642.89377.74333.27362.49380.83

Principal Dimensions by Steve Llanso of Sweat House Media

ClassD-6D-7D-8D-9D-9 1/2
Locobase ID8502 8503 8504 8505 8506
RailroadTexas & Pacific (T&P)Texas & Pacific (T&P)Texas & Pacific (T&P)Texas & Pacific (T&P)Texas & Pacific (T&P)
CountryUSAUSAUSAUSAUSA
Whyte4-6-04-6-04-6-04-6-04-6-0
Number in Class617126611
Road Numbers224-229239-244,-264-274245-256257-263, 275-316, 324-338275-277, 312, 326, 332, 334, 358-360
GaugeStdStdStdStdStd
Number Built61712662
BuilderT&PseveralRogersvariousT&P
Year1898189819001916
Valve GearStephensonStephenson or WalschStephenson or WalschaertStephensonWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)11.50 / 3.5113 / 3.9612 / 3.6612.75 / 3.8912.75 / 3.89
Engine Wheelbase (ft / m)22.50 / 6.8624 / 7.3222.83 / 6.9623.42 / 7.1423.42 / 7.14
Ratio of driving wheelbase to overall engine wheelbase 0.51 0.54 0.53 0.54 0.54
Overall Wheelbase (engine & tender) (ft / m)49.35 / 15.0451.71 / 15.7649.71 / 15.1552 / 15.8553.50 / 16.31
Axle Loading (Maximum Weight per Axle) (lbs / kg)
Weight on Drivers (lbs / kg)91,500 / 41,504118,000 / 53,52495,000 / 43,091122,000 / 55,338127,500 / 57,833
Engine Weight (lbs / kg)131,500 / 59,647153,000 / 69,400125,000 / 56,699158,000 / 71,668160,500 / 72,802
Tender Loaded Weight (lbs / kg)85,780 / 38,90999,964 / 45,343147,800 / 67,041122,000 / 55,338122,163 / 55,412
Total Engine and Tender Weight (lbs / kg)217,280 / 98,556252,964 / 114,743272,800 / 123,740280,000 / 127,006282,663 / 128,214
Tender Water Capacity (gals / ML)4500 / 17.056000 / 22.736000 / 22.736500 / 24.626500 / 24.62
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)2500 / 94632800 / 10,5982800 / 10,5982800 / 10,5982790 / 10,560
Minimum weight of rail (calculated) (lb/yd / kg/m)51 / 25.5066 / 3353 / 26.5068 / 3471 / 35.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)63 / 160067 / 170263 / 160063 / 160067 / 1702
Boiler Pressure (psi / kPa)165 / 11.40190 / 13.10190 / 13.10200 / 13.80200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)19" x 24" / 483x61019" x 26" / 483x66019" x 24" / 483x61020" x 26" / 508x66020" x 26" / 508x660
Tractive Effort (lbs / kg)19,288 / 8748.9022,624 / 10262.0922,210 / 10074.3028,063 / 12729.1826,388 / 11969.41
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.74 5.22 4.28 4.35 4.83
Heating Ability
Tubes (number - dia) (in / mm)240 - 2" / 51285 - 2" / 51230 - 2" / 51270 - 2" / 51153 - 2" / 51
Flues (number - dia) (in / mm)24 - 5.375" / 137
Flue/Tube length (ft / m)13.25 / 4.0413.75 / 4.1913.17 / 4.0113.33 / 4.0613.33 / 4.06
Firebox Area (sq ft / m2)165 / 15.33172 / 15.98175 / 16.26192 / 17.84192 / 17.84
Grate Area (sq ft / m2)21.50 / 231 / 2.8823 / 2.1435 / 3.2536 / 3.35
Evaporative Heating Surface (sq ft / m2)1835 / 170.542159 / 200.651771 / 164.532082 / 193.491711 / 159.01
Superheating Surface (sq ft / m2)370 / 34.39
Combined Heating Surface (sq ft / m2)1835 / 170.542159 / 200.651771 / 164.532082 / 193.492081 / 193.40
Evaporative Heating Surface/Cylinder Volume232.87253.11224.75220.32181.06
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation35485890437070007200
Same as above plus superheater percentage35485890437070008496
Same as above but substitute firebox area for grate area27,22532,68033,25038,40045,312
Power L1584875096699676014,182
Power MT422.71420.88466.38366.47735.67

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