In 1916, the American Locomotive Company delivered three "Mikado" type locomotives to the Ann Arbor Railroad. These locomotives were designated as Class H and were assigned road numbers 180-182. They had 63" diameter drivers, 27" x 30" cylinders, a 185 psi boiler pressure and they exerted 54,588 pounds of tractive effort and each weighed 294,500 pounds. The firebox area was 262 square feet. The evaporative heating surface was 3,905, square feet and with the superheater the combined heating surface was 4,815 square feet.
Another five 2-8-2s arrived from ALCO in 1923. This group was designated as Class H-1 and the design was similar to the Class H "Mikados" except they were 3,500 pounds heavier and with a 200 psi boiler pressure they exerted 59,014 pounds of tractive effort.
In 1925, the Wabash acquired control of the Ann Arbor Railroad and some of these steam locomotives wore several numbers due to an early Ann Arbor re-numbering program, and their later inclusion in the Wabash locomotive numbering order.
There are no surviving Ann Arbor 2-8-2 "Mikado" type locomotives.
| Class | Qty. | Road Number | Later Numbers | Year Built | Builder | Notes |
|---|---|---|---|---|---|---|
| H | 3 | 180-182 | 2480-2482 | 1916 | ALCO | 1 |
| H-1 | 5 | 183-187 | 2490-2494 | 1923 | ALCO | 2 |
Data from AA-M&LS 1 - 1928 locomotive diagram book dated supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 56592-56594 in December 1916.
This small Michigan railroad bought its motive power in small batches that had differences even within the class. The first two had the EHS (3,905 sq ft) and the number of small tubes (239) as shown. The 182 had eight more small tubes (247), which increased its total heating surface to 3,991 sq ft. Seven years later, the AA bought 5 more built to a slightly different design; see Locobase 7341.
The Wabash later took over the Ann Arbor and renumbered this class as shown.
Data from AA-M&LS 1 - 1928 locomotive diagram book dated supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. Works numbers were 64308-64310 in July 1923 and 64902-64903 in October.
These were the post-World War One Mikes for the Ann Arbor. They were middle-of-the-pack 2-8-2s apparently based on the pre-war H class (Locobase 7341). For an increase of two tons of adhesion weight, they gained some addtional heating surface. Moreover, their boilers steamed harder and raised calculated tractive effort by 5,000 lb.
When the Wabash took over the Ann Arbor, they renumbered this class 2490-2494.
| Principal Dimensions by Steve Llanso of Middle Run Media | ||
|---|---|---|
| Class | H / K6 | H1 / K7 |
| Locobase ID | 7340 | 7341 |
| Railroad | Ann Arbor (AA) | Ann Arbor (AA) |
| Country | USA | USA |
| Whyte | 2-8-2 | 2-8-2 |
| Number in Class | 3 | 5 |
| Road Numbers | 180-182 / 2480-2482 | 183-187 / 2490-2494 |
| Gauge | Std | Std |
| Number Built | 3 | 5 |
| Builder | Alco-Brooks | Alco-Brooks |
| Year | 1917 | 1923 |
| Valve Gear | Baker | Walschaert |
| Locomotive Length and Weight | ||
| Driver Wheelbase (ft / m) | 16.50 / 5.03 | 16.50 / 5.03 |
| Engine Wheelbase (ft / m) | 35.17 / 10.72 | 35.17 / 10.72 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.47 | 0.47 |
| Overall Wheelbase (engine & tender) (ft / m) | 67.29 / 20.51 | 67.87 / 20.69 |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | ||
| Weight on Drivers (lbs / kg) | 224,500 / 101,832 | 228,500 / 103,646 |
| Engine Weight (lbs / kg) | 294,500 / 133,583 | 298,000 / 135,171 |
| Tender Loaded Weight (lbs / kg) | 176,000 / 79,832 | 179,500 / 81,420 |
| Total Engine and Tender Weight (lbs / kg) | 470,500 / 213,415 | 477,500 / 216,591 |
| Tender Water Capacity (gals / ML) | 9000 / 34.09 | 9000 / 34.09 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 15 / 14 | 15 / 14 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 94 / 47 | 95 / 47.50 |
| Geometry Relating to Tractive Effort | ||
| Driver Diameter (in / mm) | 63 / 1600 | 63 / 1600 |
| Boiler Pressure (psi / kPa) | 185 / 1280 | 200 / 1380 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 27" x 30" / 686x762 | 27" x 30" / 686x762 |
| Tractive Effort (lbs / kg) | 54,588 / 24760.73 | 59,014 / 26768.33 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.11 | 3.87 |
| Heating Ability | ||
| Tubes (number - dia) (in / mm) | 239 - 2" / 51 | 250 - 2" / 51 |
| Flues (number - dia) (in / mm) | 38 - 5.375" / 137 | 43 - 5.375" / 137 |
| Flue/Tube length (ft / m) | 20.50 / 6.25 | 20 / 6.10 |
| Firebox Area (sq ft / m2) | 262 / 24.35 | 257 / 23.88 |
| Grate Area (sq ft / m2) | 70.40 / 6.54 | 70.40 / 6.54 |
| Evaporative Heating Surface (sq ft / m2) | 3905 / 362.92 | 4063 / 377.60 |
| Superheating Surface (sq ft / m2) | 910 / 84.57 | 1062 / 98.70 |
| Combined Heating Surface (sq ft / m2) | 4815 / 447.49 | 5125 / 476.30 |
| Evaporative Heating Surface/Cylinder Volume | 196.43 | 204.38 |
| Computations Relating to Power Output (More Information) | ||
| Robert LeMassena's Power Computation | 13,024 | 14,080 |
| Same as above plus superheater percentage | 15,499 | 17,037 |
| Same as above but substitute firebox area for grate area | 57,679 | 62,194 |
| Power L1 | 13,098 | 15,746 |
| Power MT | 514.50 | 607.68 |
