Birmingham Southern 4-6-4 "Hudson" Locomotives in the USA

Class Details by Steve Llanso of Sweat House Media

Class 4-6-4 30.9.3 (Locobase 7310)

Data from TCI&RR 1949 locomotive diagrams supplied by Allen Stanley in May 2005 from his extensive Rail Data Exchange; and Alco specifications originally compiled by Tom Lawson of Birmingham Rails and supplied to Locobase in a 7 June 2022 email from John Stewart, acknowledged here with many thanks.

Thanks to the Tom Lawson/John Stewart information, Locobase now has firmer ground for establishing the origins of 450's design. Locobase had earlier determined that the 450 was similar in many ways to the CNJ's 4-6-4Ts of the same era (Locobase 6530). He also estimated superheater area based on a similar engine (Boston & Albany D-2, a 2-6-6-T; see Locobase 3844), which had not just the same number and diameter of flues and flue length, but very nearly the same evaporative heating surface as well.

Neither of those speculations fell very wide of the true mark, which is found in Alco's specification number A-10573 dated 10 December 1920. It stated that the TCI&RR's 450 was "based on order Q-241 ([works numbers] 54894-54899) built for the Grand Trunk Ry. [see Locobase 2454], but modified to suit." Much remained unchanged, but 450's boiler held two more flues. In both designs, firebox heating surface area included 31 sq ft (2.88 sq m) from four 3" (76.2 mm) arch tubes.

Superintendent Henry's review of the spec, dated 11 May 1922, required a change from the specified 10 1/2 K Sellers Non-Lifting injectors to 10 1/2 N Lifting injectors. The note also added top crosshead gibs in addition to the bottom set; these had 1 3/4" (44.5 mm) side bearings on the slide bar.

(TCI&RR's diagram plainly shows the evaporative heating surface area (tube and firebox together) as 1,692 sq ft (157.19 sq m), but a calculation of tube and flue external areas shown the figure given in Alco's and Locobase's specs.)

Steamtown's Special History Study of the Canadian 4-6-4T in its possession -- accessed 15 December 2005 at [] -- spells out the TCI&RR's use of its one "Baltic tank", which was "...hauling a company commuter passenger tram connecting downtown Birmingham, at a depot at 14th Street and 1st Avenue, North, with company mines at Hamilton, Edgewater, Docena, Wenonah, Ishkoda, and Muscoda, Alabama, and possibly others."

The history adds that by 1932, the grip of the Great Depression rendered this service superfluous. At that point, the engine took up new duties as a hostler's switcher. 450 was scrapped in 1945, the account concludes. [Locobase wonders if the scrap steel from 450 fed a "heat" in one of TCI's foundries.]

The TCI&RR supported coal mining in Southeastern Tennessee and Alabama, particularly the Ensley Works in Birmingham, which was a leading force in the development of the South's coal, iron, and steel industry. TCI was sufficiently massive to appear on the Dow Jones list of leading industrial stocks from May 1896 to April 1905. Soon afterward, the Panic of 1907 left TCI owing $5 million, which the company was forced to repay by allowing US Steel to buy its stock. It remained a subsidiary of US Steel until 1988.)

See [] (accessed 14 December 2005) for an account of how the TCI&RR made extensive use of the black-convict labor lease system in the 1880s. (See [], accessed 14 December 2005). The Coal & Pig Iron Route wound through Tennessee and Alabama. By the end of the century, however, the railroad had distanced itself from that form of labor.

Principal Dimensions by Steve Llanso of Sweat House Media

Class4-6-4 30.9.3
Locobase ID7310
RailroadBirmingham Southern (TCI&R)
Number in Class1
Road Numbers450
Number Built1
Valve GearWalschaert
Locomotive Length and Weight
Driver Wheelbase (ft / m)15.67 / 4.78
Engine Wheelbase (ft / m)39.37 / 12
Ratio of driving wheelbase to overall engine wheelbase 0.40
Overall Wheelbase (engine & tender) (ft / m)39.37 / 12
Axle Loading (Maximum Weight per Axle) (lbs / kg)51,200 / 23,224
Weight on Drivers (lbs / kg)146,000 / 66,225
Engine Weight (lbs / kg)264,000 / 119,749
Tender Loaded Weight (lbs / kg)
Total Engine and Tender Weight (lbs / kg)264,000
Tender Water Capacity (gals / ML)3500 / 13.26
Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT)5 / 5
Minimum weight of rail (calculated) (lb/yd / kg/m)81 / 40.50
Geometry Relating to Tractive Effort
Driver Diameter (in / mm)63 / 1600
Boiler Pressure (psi / kPa)200 / 13.80
High Pressure Cylinders (dia x stroke) (in / mm)21" x 26" / 533x660
Tractive Effort (lbs / kg)30,940 / 14034.16
Booster (lbs)1
Factor of Adhesion (Weight on Drivers/Tractive Effort) 4.72
Heating Ability
Tubes (number - dia) (in / mm)177 - 2" / 51
Flues (number - dia) (in / mm)28 - 5.375" / 137
Flue/Tube length (ft / m)11.83 / 3.61
Firebox Area (sq ft / m2)204 / 18.95
Grate Area (sq ft / m2)47 / 4.37
Evaporative Heating Surface (sq ft / m2)1756 / 163.14
Superheating Surface (sq ft / m2)342 / 31.77
Combined Heating Surface (sq ft / m2)2098 / 194.91
Evaporative Heating Surface/Cylinder Volume168.52
Computations Relating to Power Output (More Information)
Robert LeMassena's Power Computation9400
Same as above plus superheater percentage10,904
Same as above but substitute firebox area for grate area47,328
Power L111,798
Power MT534.45

  • TCIR 450 (Builder's photo courtesy Tom Lawson)
  • TCIR 450 (Photo courtesy Tom Lawson)
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Wes Barris