Data from MP SUBS 7 - 1935 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 62889-62893 in January 1921
This quintet of latter-day Ten-wheelers had a relatively long stride under an average-sized boiler and grate.
They retained their original numbers when the NOT&M motive power stud was absorbed by parent Missouri Pacific in 1925. The TN-69s remained on the rolls throughout World War Two. The first to retire was the 387 in March 1950, the others leaving one at a time until the 385 completed the process in December 1953.
| Principal Dimensions by Steve Llanso of Middle Run Media | |
|---|---|
| Class | TN-69 - 29.6 |
| Locobase ID | 7761 |
| Railroad | New Orleans, Texas & Mexico (NOT&M/MP) |
| Country | USA |
| Whyte | 4-6-0 |
| Number in Class | 5 |
| Road Numbers | 385-389 |
| Gauge | Std |
| Number Built | 5 |
| Builder | Alco-Brooks |
| Year | 1921 |
| Valve Gear | Walschaert |
| Locomotive Length and Weight | |
| Driver Wheelbase (ft / m) | 15 / 4.57 |
| Engine Wheelbase (ft / m) | 26.92 / 8.21 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.56 |
| Overall Wheelbase (engine & tender) (ft / m) | 62.25 / 18.97 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | |
| Weight on Drivers (lbs / kg) | 140,000 / 63,503 |
| Engine Weight (lbs / kg) | 187,000 / 84,822 |
| Tender Loaded Weight (lbs / kg) | 153,000 / 69,400 |
| Total Engine and Tender Weight (lbs / kg) | 340,000 / 154,222 |
| Tender Water Capacity (gals / ML) | 7500 / 28.41 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 3000 / 11,355 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 78 / 39 |
| Geometry Relating to Tractive Effort | |
| Driver Diameter (in / mm) | 69 / 1753 |
| Boiler Pressure (psi / kPa) | 200 / 1380 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 21.5" x 26" / 546x660 |
| Tractive Effort (lbs / kg) | 29,611 / 13431.34 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.73 |
| Heating Ability | |
| Tubes (number - dia) (in / mm) | 175 - 2" / 51 |
| Flues (number - dia) (in / mm) | 28 - 5.375" / 137 |
| Flue/Tube length (ft / m) | 15 / 4.57 |
| Firebox Area (sq ft / m2) | 180 / 16.72 |
| Grate Area (sq ft / m2) | 32.70 / 3.04 |
| Evaporative Heating Surface (sq ft / m2) | 2145 / 199.35 |
| Superheating Surface (sq ft / m2) | 485 / 45.07 |
| Combined Heating Surface (sq ft / m2) | 2630 / 244.42 |
| Evaporative Heating Surface/Cylinder Volume | 196.25 |
| Computations Relating to Power Output (More Information) | |
| Robert LeMassena's Power Computation | 6540 |
| Same as above plus superheater percentage | 7717 |
| Same as above but substitute firebox area for grate area | 42,480 |
| Power L1 | 15,593 |
| Power MT | 736.64 |