At the same time that the B & W was taking delivery of this passenger engine, Wilmarth's Union Works in South Boston was securing orders for several locomotives from the Hudson River Railroad. The Nathan Hale (named for a railroader, not the spy) had a pressure setting of 110 psi, but the official trials BP was 99 psi.
Angus Sinclair described Wilmarth as "...an excellent mechanic and enterprising engineer, [who] had his career as locomotive builder ended through a contract he took to build a large number of locomotives [25, #167-187] each weighing 37 tons] for the Erie at a ruinously low price."
See William P Hunt, "Letters -- Seth Wilmarth and His Locomotives", Railroad Gazette, Volume XLIII, No 14 (4 October 1907), p. 383, in which he gives a full description of the consequences of Wilmarth's attempt to build locomotives for the Erie:
"Boston. Mass., Oct. 1, 1907.
"In reading the article by Mr. Caruthers in your issue of Sept. 27, 'Seth Wilmarth Locomotives,' it occurs to me that I may supply some features of Mr. Wilmarth's career that Mr. Caruthers was not able to find. At the time these engines were built I was a clerk in the office of the South Boston Iron Company, whose plant was adjoining to that of Mr. Wilmarth, and I was well acquainted with Mr. Wilmarth. His business originally was a general machine shop, until he took up the building of locomotives, and up to this time his business was successful and prosperous; but after a few years he made a contract with the Erie Railroad which brought him to bankruptcy, and his plant and business were sold out. I do not remember about his career after his bankruptcy, but have an impression that he was appointed to some superintendence at the Boston Navy Yard. I understand Mr. Wilmarth made a contract with the Erie Railroad for some 25 or 30 locomotives, which was a very large undertaking at that time, especially for a man of Mr. Wilmarth's limited means, and who was (as was generally the case with industrial manufacturers at that time) obliged to buy bis supplies on credit. When he had fairly launched in the manufacture of these locomotives he found that the Erie Railroad could not pay cash, and he was obliged to take notes in payment, and when these notes became due he was obliged to renew them. This situation destroyed Mr. Wilmarth's credit, and he was obliged to realize on his notes as best he could. I understand that for a while he sold these notes to Daniel Drew, who was a banker as well as trustee of the Erie Railroad, at a discount, but this management was short-lived, and he was forced into bankruptcy. ...
"[signed] Wm. p. Hunt,
President, Hunt-Splller Manf'g. Corporation."
NB: Boiler pressure is an estimate.
The boiler pressure is estimated. The grate area, firebox heating surface, and total heating surface are calculated. See Locobase 5552 for full explanation. While the dimensions are not derived from actual measurement, they agree with those of similar American locomotives of the era.
Corbin & Kerka also fill in the history of this, the first Chicago & Aurora locomotive. Originally delivered to the B & W along with a sister, Neptune (works #94 & 96) in March and April 1847, the Rocket traveled to the Michigan Central, who sold it to the Chicago & Aurora in July 1852. By then it was quite a small locomotive. Even so, it made Hammonds' inventory, only to be retired in April 1859.
|Specifications by Steve Llanso of Sweat House Media|
|Railroad||Boston & Worcester||Boston & Worcester|
|Number in Class||1||2|
|Locomotive Length and Weight|
|Driver Wheelbase (ft)|
|Engine Wheelbase (ft)|
|Ratio of driving wheelbase to overall engine wheebase|
|Overall Wheelbase (engine & tender) (ft)|
|Axle Loading (Maximum Weight per Axle) (lbs)|
|Weight on Drivers (lbs)|
|Engine Weight (lbs)||47,095||38,000|
|Tender Loaded Weight (lbs)|
|Total Engine and Tender Weight (lbs)|
|Tender Water Capacity (gals)|
|Tender Fuel Capacity (oil/coal) (gals/tons)|
|Minimum weight of rail (calculated) (lb/yd)|
|Geometry Relating to Tractive Effort|
|Driver Diameter (in)||66||60|
|Boiler Pressure (psi)||110||87|
|High Pressure Cylinders (dia x stroke) (in)||16" x 20"||15" x 18"|
|Tractive Effort (lbs)||7253||4992|
|Factor of Adhesion (Weight on Drivers/Tractive Effort)|
|Firebox Area (sq ft)||58.20||34.94|
|Grate Area (sq ft)||10.67||8.74|
|Evaporative Heating Surface (sq ft)||695||600|
|Superheating Surface (sq ft)|
|Combined Heating Surface (sq ft)||695||600|
|Evaporative Heating Surface/Cylinder Volume||149.33||162.97|
|Computations Relating to Power Output (More Information)|
|Robert LeMassena's Power Computation||1174||760|
|Same as above plus superheater percentage||1174||760|
|Same as above but substitute firebox area for grate area||6402||3040|