Piecing together the data from this account and from John White's (1968) figure 63 gives us the dimensions and numbers we have. Like the Hudson River's Superior, the Spring Green rode on a slab-rail frame, rather than the far more common two-rail bar frame. A single deep rail ran from the smokebox to the first axle horn to which it was scarf-joined. Perhaps the Superior's tube-sheet weaknesses affected this design, for there are many fewer tubes in the slender boiler. A somewhat retrograde feature was the slanted cylinders, although in many other respects this was a state-of-the-art American design.
Zlatkovich says that the M&M is a predecessor of the later Milwaukee Road, although it went bankrupt soon after it purchased this engine. Reorganized as the Milwaukee & Prairie du Chien, it was then sold to the Milwaukee & St Paul in 1867. Arguing that the M&M named its locomotives after towns on the route, Zlatkovich is convinced by John H. White's suggestion that this engine was dubbed Spring Green rather than Spring Garden.
(Breese-Kneeland records show three more delivered to the M&M in the same month as the Spring Green. They may have been built to the same design and were named Auca, S J Collons, and Defiance.)
Southport was sold to the Arizona and South Eastern in 1889 (sources differ on whether it was February or July), EP&SW #1 operated until 1903, rostered until 1909, and restored for display in that year. EP&SW displayed the engine until 1960, when it was donated to Texas Western University and placed near the Centennial Museum.
NB: The direct heating surface (including the firebox heating surface) is an estimate calculated by subtracting the calculated tube heating surface from the reported total evaporative heating surface.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Milwaukee & Mississippi|
|Number in Class||1|
|Locomotive Length and Weight|
|Ratio of driving wheelbase to overall engine wheebase||0.33|
|Overall Wheelbase (engine & tender)||41.67'|
|Axle Loading (Maximum Weight per Axle)|
|Weight on Drivers|
|Engine Weight||52000 lbs|
|Tender Light Weight|
|Total Engine and Tender Weight|
|Tender Water Capacity|
|Tender Fuel Capacity (oil/coal)|
|Minimum weight of rail (calculated)||0|
|Geometry Relating to Tractive Effort|
|Boiler Pressure||110 psi|
|Cylinders (dia x stroke)||15" x 22"|
|Tractive Effort||7232 lbs|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)|
|Firebox Area||77 sq. ft|
|Evaporative Heating Surface||793 sq. ft|
|Combined Heating Surface||793 sq. ft|
|Evaporative Heating Surface/Cylinder Volume||176.23|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||0|
|Same as above plus superheater percentage||0|
|Same as above but substitute firebox area for grate area||8470|