Class S-1a (Locobase 270)

Data from the 1946 guide to Dimensions and Classifications of Locomotives seen on http://www.rr-fallenflags.org/nyc/nyc-lb46.pdf (May 2003)

Firebox heating surface included 57 sq ft of arch tubes. Don't look in the specifications for this engine's widely touted abilities. This class had a high adhesive weight, roller bearings all around, Baker valve gear, a large grate area, and valve ports designed to help the engine draw air evenly across the fire and through the tubes. They are easily recognized by their long, almost straight boiler line and "elephant ear" exhaust lifters. Note the enormous tender capacity.

This was the prototype; see Locobase 5583 for the production version S-1b. The 75" drivers were soon replaced by the 79" drivers of the S-1b.

Class S-1b (Locobase 5582)

Data from the 1946 guide to Dimensions and Classifications of Locomotives seen on http://www.rr-fallenflags.org/nyc/nyc-lb46.pdf (May 2003)

Firebox heating surface included 57 sq ft of arch tubes. This is the production version of this remarkable design; see Locobase 207 for the prototype. Paul Kiefer, Chief of Motive Power for the NYC, is credited for the scale and quality of this design.

Tests with the prototype had shown that pulling power didn't suffer much when 79" drivers were fitted. The result was one of the finest steam passenger locomotives ever built. Integrally cast, one-piece frame and cylinders, roller bearings on all axles and on the side rod ... all the mod cons. Brian Hollingsworth (1982) notes that Baker valve gear had no sliding surfaces, so they could be fitted with needle bearings. These must have been exceptionally smooth-riding locomotives. Moreover, says Hollingsworth, the valve ports were "...sharp on the steam side, but slightly rounded on the exhaust side ... [easing] the sharpness of the blast beats, thereby evening out the draft on the fire."

And in addition to having that immense 7-axle pedestal tender to carry 92,000 lb of coal, the S-1s made use of an extensive network of trackpans to fill the tenders on the fly. As a result, the class had to make only one fuel stop during the New York-Chicago run. One of these -- 6024 -- accumulated 288,849 miles in only 11 months.

One S-1b was fitted with Caprotti poppet-valve gear and redesignated S-2a.

David R Stephenson, writing in the May 2005 Chesapeake and Ohio Historical Magazine (reproduced online at http://www.findarticles.com/p/articles/mi_qa3943/is_200505/ai_n1342634, accessed 24 Oct 2005), puts the S-1b in clear perspective when he compares it to the Pennsy's classic T-1 duplex 4-4-4-4 (Locobase 348). After noting that the duplex solution was conceived to redress a potential problem that never quite materialized, he offers the S-1b as trump:

"Here was a locomotive," Stephenson 's verdict concludes, "that could match the T-1 at all but the highest speeds, and do it day-in and day-out without special treatment. It was moderately sized and could go almost anywhere. It didn't require particularly deft handling, was very reliable, could operate in most types of service, and didn't require specialized maintenance."