New York, New Haven & Hartford 4-6-4 "Hudson" Locomotives in the USA

Class I-5 (Locobase 187)

Data from 1947 Locomotive Cyclopedia and from NH 1962 Steam Locomotives diagram book supplied in March 2005 by Allen Stanley from his extensive Rail Data Exchange collection. See also Kenneth Cartwright, "The New Haven Streamlined Locomotives", Baldwin Locomotive Magazine, Volume 15, No 4 (April 1937), pp. 2- (Many thanks to Chris Hohl for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error.) Works numbers ran 61964-61973 in 1936

Firebox heating surface included 139 sq ft of syphons (3) and 81 sq ft of combustion chamber. The cylinders were fed through 11" (279 mm) piston valves. The New Haven calculated water evaporation at 59,359 lb (26,925 kg) /hour of which the direct heating surface accounted for 26,400 lb (11,975 kg)/hour. This could be set against the max consumption of 51,626 lb (23,417 kg) /hour, yielding a boiler factor of 115%.

Other features included an integral cast frame and roller bearings on the drivers (Timkens on 1401-1404, SKF on the rest) and ASF roller bearings on the leading and trailing trucks.

The Catskill Archive of old writeups about steam locomotives includes a late 1930s article on the I-5 -- [], accessed 22 January 2007. According to the account, Baldwin's hearty Hudsons responded to a requirement that the new engines be able to muscle 12-car, 830-ton (755-tonne) trains up the Sharon Heights 0.6-0.7% grades at 60 mph (97 kph). Cartwright, a New Haven mechanical engineer, noted the railroad's typical schedule and commented: "Obviously , if a train is frequently slowed down to 40 or 45 miles per hour, it i snecessdary to get the speed back to 70 or 80 miles per hour as quickly as possible if right schedules are to be maintained." An additional requirement that the locomotives be able to run on the lighter-built New Haven-Springfield section limited weight.

The New Haven received everything they asked for. Every day eight of the ten streamliners worked the Merchant's Limited between New Haven and Boston on 24 daily trips with the other two in repair or reserve. The I-5s were reliable, but their latent power could not be fully exploited because of speed restrictions on the line.