Class 1986 (Locobase 11139)

Data from Schenectady Locomotive Works, Illustrated Catalogue of Simple and Compound Locomotives (Philadelphia: J B Lippincott, 1897), pp. 121-122.

This was the cross-compound trial horse version of the Mastodon class described in Locobase 11138.

Class 2012 (Locobase 11136)

Data from Schenectady Locomotive Works, Illustrated Catalogue of Simple and Compound Locomotives (Philadelphia: J B Lippincott, 1897), pp. 112-113.

Class 369 (Locobase 11138)

Data from Schenectady Locomotive Works, Illustrated Catalogue of Simple and Compound Locomotives (Philadelphia: J B Lippincott, 1897), pp. 118-119..

Class GC / 367 (Locobase 13308)

Data from Engineering News and Railway Journal, Volume 25, No. 9 (28 February 1891), p. 193.

Although they'd generated good results testing the 1986 (Locobase 11139) beginning in 1889, the Espee's Superintendent of Motive Power H J Small went back to Schenectady two years later for a slightly revised Twelve-wheeled cross-compound. This engine had been delivered as a simple-expansion locomotive, but returned to be fitted with the Odd-Couple compound arrangement. The 367 was specified to use A J Pitkin's intercepting valve, which was designed to improve starting power by allowing live steam into the LP cylinder.

Class TW-1 (Locobase 7253)

Data from SP Menke All-Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection and "Heavy 12-Wheeld Freight Locomotive for the Central Pacific R. R.", Locomotive Engineering (March 1895), p. 39.

LEMJ waxed in the enthusiastic affirmation of American industry characteristic of the time in saluting the arrival of this Twelve-wheeler design: "The cut below shows the heaviest locomotive ever built at the Schenectady Works, where 4,233 were turned out before this one.

"This engine may be taken as a good type of the state of the art of heavy locomotive construction for American mountain service, in this year of grace 1895.

"This engine is wanting in nothing to make it safe, economical, and efficient for heavy, hard work."

An insight into the relative merits of various aspects of locomotive design opens up as the author says: "We must commend the designer for not getting enthusiastic about huge ports and long valve travel on this engine. Coal is worth from $6 to $10 a ton on the Sierra Nevada mountains. The big things are where most wanted here-the boiler and cylinders."

Class TW-2 (Locobase 7254)

Data from SP Menke All-Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

These Twelve-wheelers entered service in the mid-1890s as cross-compounds. By May 1, 1930 (the date of the diagram) they were not compounds and they had relatively small cylinders. TW-2a and TW-2b had slight variations in tube count and thus evaporative heating surface.

Class TW-3 (Locobase 7255)

Data from SP Menke All-Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

The TW-2s and TW-3 classes were virtually identical, with the TW-3 having a very slightly larger grate. TW-3bs later had a few more boiler tubes (266), giving a total of 1,899 sq ft of evaporative heating surface.

Class TW-4 (Locobase 7256)

Data from SP Menke All-Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection. Works numbers were 1409-1413 in December 1882, 1414-1433 in January-October 1883.

According to a compilation of Cooke locomotives by B.Rumary (25 Kingscombe, Gurney Slade, Radstock, BA3 4TH, ENGLAND) and supplied to Locobase by Allen Stanley in March 2004, the only Twelve-wheelers built for the Espee by this Paterson, NJ firm were the 25 in a batch produced in December 1882-October 1883.

Class TW-4c (Locobase 7257)

Data from SP Menke All-Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

For some reason, some of the TW-4s lost 40 of their boiler tubes at some point while the rest of the design retained its earlier dimensions.

Class TW-6 (Locobase 7258)

Data from SP Menke All-Time Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

This set of Twelve-wheelers were very similar to the TW-4s from Cooke (Locobase 7257), but had fewer tubes and smaller drivers.

Class TW-7 (Locobase 8938)

Data from Arthur Mellen Wellington, The Economic Theory of the Location of Railways: An Analysis of the Location of Railways (New York: Chapman & Hall, limited, 1887), 410.

Wellington reports that this Mastodon hauled 20 loaded cars weighing 422 tons up a 2% grade. The National Park Services account of the Sacramento shops reports that this locomotive was so successful that the railroad ordered 20 more from Cooke. Locobase cannot find those engines listed on a Cooke inventory..

Class TW-8 (Locobase 7259)

Data from http://www.steamlocomotive.info entry on SP #2914 and from SP 7-1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

This class was built originally as cross-compound with 23" HP and 35" LP cylinders, the boiler using 332 tubes and a total heating surface of 3,025.85 sq ft; see Locobase 12592.

Originally delivered as a coal burner but converted to oil-burning soon after its arrival. he class was later converted to the simple-expansion and sometime after its simpling, the class was superheated. That upgrade is shown in Locobase 6290.

Class TW-8 - cross-compound (Locobase 12592)

Data from "Southern Pacific Schenectady Mastodon," Locomotive Engineering, Volume 12, No 1 (January 1899), p. 29.

Schenectady promoted a brief vogue in large, two-cylinder cross-compound engines to several western railroads. These were the last in a series of such engines for the Souther Pacific and they were big and featured the long stroke usually found on 4-8-0s.

They were almost immediately converted to oil-firing. Not too long afterwards, the class received a set of simple-expansion cylinders; see Locobase 7259.

NB: The Missouri Pacific was credited with possibly just one cross-compound of essentially identical dimensions in a 1903 American Engineering and Railroad Journal table. See Locobase 5333.

Class TW-8s (Locobase 6290)

Data from http://www.steamlocomotive.info entry on SP #2914 and from SP 7-1951 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

Originally delivered as a coal burner but converted to oil-burning soon after its arrival. And it entered service as a cross-compound, but was later converted to simple-expansion and some time after its simpling, the class was superheated, a unique event among SP Twelve-wheeler classes. The resulting data is shown here.

The Kern County (Calif) Museum website -- http://www.kcmuseum.org/stories/storyReader$84 (visited 12 Aug 2004) -- summarizes 2914's career as follows:

"One of the largest engines of its time, it hauled freight over the Tehachapi Mountains through the Tehachapi Loop to Mojave and north to Fresno and hauled oil to the west side of the San Joaquin Valley on the Sunset Railway Line to the oilfields in western Kern County near Taft and McKittrick. About 1945 this locomotive was used as a switch engine and ended its career switching cars in the Southern Pacific yards in East Bakersfield."

The class was scrapped in 1949-1953, except for 2914, which was donated to the Bakersfield museum in 1955.