Like the Consolidations that immediately preceded them into service, this trio of Mikes were slightly altered USRA Light Mikes that soon acquired a variety of enhancements to their firebox, which resulted in a sizable amount of direct heating surface. The combustion chamber ahead of the firebox supplied 55 sq ft (5.1 sq m) and arch tubes another 27 sq ft (2.5 sq m). A single Alco (road number 24) joined them a year later; see Locobase 7867
When modified later, the firebox received two thermic syphons that contributed 79 sq ft (7.35 sq m) to direct heating surface at the cost of two arch tubes. The two remaining arch tubes added 15 sq ft (1.4 sq m) for a total firebox heating surface area of 355 sq ft (33 sq m) or over 9% of evaporative heating surface area of 3,850 sq ft (357.8 sq m). By then adhesion weight had increased by more than 4 1/2 short tons to 233,510 lb (105,918 kg) and total engine weight rose by over 6 1/2 tons to 311,440 lb (141,267 kg). Much of the weight gain may be attributable to the Elesco feed water heater
Chris Hohl pointed out that the original tender capacity was 16 tons of coal. Tender weight remained approximately the same despite the addition of three more short tons (2.7 metric tonnes) of coal. This enlargement also accounts for the engine and tender wheelbase from its original 71 ft 6 1/4 in (23.32 m) to the 75 ft 5 1/2 in shown in the specs.
A year after the three Baldwins arrived on the D & TS (Locobase 7866), Alco delivered a single 2-8-2 produced in September 1925. Over time the firebox underwent the same transformation, deleting two of four arch tubes in favor of 79 sq ft (7.35 sq ft) of thermic syphons and leaving 13 sq ft (1.2 sq m) of arch tubes.
The D&TSL added this quartet to its stud of Mikados three years after the delivery of the lone Alco (Locobase 7867). The design continued the heritage of the USRA Light Mikado on which it was originally based, but there were changes.
Boiler tubes were 20" (508 mm) shorter and direct heating surface supplemented the two arch tubes (14 sq ft/ 1.3 sq m) with 55 sq ft (5.11 sq m) from the combustion chamber and 79 sq ft (7.34 sq m) in two thermic syphons. In addition, the design used an Elesco feed water heater. Piston valve measured 14" (356 mm) in diameter.
When delivered, the tenders carried 14 tons of coal and weighed approximately 190,000 lb (86,183 kg). By the end of their careers, the class's tenders carried more coal and weighed ten tons more.
Nine years after Baldwin had delivered the last of the earlier Mikados (Locobase 7868), Lima contributed three more to a slightly revised edition of the USRA Light Mikado. The boiler traded 26 small tubes for 5 more flues, which increased the superheater fraction of total heating surface area. The grate remained the same, but combined arch tube and syphon area shrank by 11 sq ft. And inevitably overall weight rose.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Detroit & Toledo Shore Line (CNR)||Detroit & Toledo Shore Line (CNR)||Detroit & Toledo Shore Line (CNR)||Detroit & Toledo Shore Line (CNR)|
|Number in Class||3||1||4||3|
|Locomotive Length and Weight|
|Driver Wheelbase (ft / m)||16.75 / 5.11||16.75 / 5.11||16.75 / 5.11||16.75 / 5.11|
|Engine Wheelbase (ft / m)||36.08 / 11||36.08 / 11||36.58 / 11.15||36.50 / 11.13|
|Ratio of driving wheelbase to overall engine wheebase||0.46||0.46||0.46||0.46|
|Overall Wheelbase (engine & tender) (ft / m)||75.46 / 23||71.37 / 21.75||76.10 / 23.20||78.21 / 23.84|
|Axle Loading (Maximum Weight per Axle) (lbs / kg)||58,850 / 26,694||58,800 / 26,671||59,570 / 27,021||60,200 / 27,306|
|Weight on Drivers (lbs / kg)||224,000 / 101,605||231,700 / 105,097||233,700 / 106,005||238,300 / 108,091|
|Engine Weight (lbs / kg)||298,000 / 135,171||311,400 / 141,249||323,010 / 146,515||324,200 / 147,055|
|Tender Loaded Weight (lbs / kg)||184,660 / 83,760||189,300 / 85,865||211,240 / 86,183||242,800 / 110,132|
|Total Engine and Tender Weight (lbs / kg)||482,660 / 218,931||500,700 / 227,114||534,250 / 232,698||567,000 / 257,187|
|Tender Water Capacity (gals / ML)||10,000 / 37.88||10,000 / 37.88||12,000 / 45.45||14,000 / 53.03|
|Tender Fuel Capacity (oil/coal) (gals/tons / ML/MT)||19 / 17.30||19 / 17.30||17 / 12.70||17 / 15.50|
|Minimum weight of rail (calculated) (lb/yd)||93||97||97||99|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in / mm)||63 / 1600||63 / 1600||64 / 1626||63 / 1600|
|Boiler Pressure (psi / kPa)||200 / 13.80||200 / 13.80||200 / 13.80||200 / 13.80|
|High Pressure Cylinders (dia x stroke) (in / mm)||26" x 30" / 660x762||26" x 30" / 660x762||26" x 30" / 660x762||26" x 30" / 660x762|
|Tractive Effort (lbs / kg)||54,724 / 24822.42||54,724 / 24822.42||53,869 / 24434.60||54,724 / 24822.42|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)||4.09||4.23||4.34||4.35|
|Firebox Area (sq ft / m2)||288 / 26.76||341 / 31.68||354 / 32.89||330 / 30.67|
|Grate Area (sq ft / m2)||66.80 / 6.21||66.90 / 6.22||66.80 / 6.21||66.80 / 6.21|
|Evaporative Heating Surface (sq ft / m2)||3785 / 351.64||3836 / 356.37||3727 / 346.25||3550 / 329.93|
|Superheating Surface (sq ft / m2)||918 / 85.28||933 / 86.68||854 / 79.34||989 / 91.91|
|Combined Heating Surface (sq ft / m2)||4703 / 436.92||4769 / 443.05||4581 / 425.59||4539 / 421.84|
|Evaporative Heating Surface/Cylinder Volume||205.32||208.08||202.17||192.57|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||13,360||13,380||13,360||13,360|
|Same as above plus superheater percentage||16,032||16,056||15,898||16,299|
|Same as above but substitute firebox area for grate area||69,120||81,840||84,252||80,520|