Class E1 (Locobase 6919)

Data from WAB 1907 and WAB 1 - 1917 Locomotive Diagram books supplied in May 2005 by Allen Stanley from his extensive collection.

As many other railroads turned to the Atlantic arrangement for express passenger locomotives, so did the Wabash beginning with this quintet from Baldwin. The purpose of the trailing axle shows clearly in the diagram as the firebox has been shifted behind the rear driving axle. But neither this class nor its successor (Locobase 6920) exploited the greater available space as a chance to enlarge the grate.

At some later point, the Wabash added 15 sq ft of arch tubes to the direct heating surface, increasing it to 184.3 sq ft.

Class E2 (Locobase 6920)

Data from WAB 1907 and WAB 1 - 1917 Locomotive Diagram books supplied in May 2005 by Allen Stanley from his extensive collection.

The Wabash turned to Richmond for its second batch of Atlantics three years after it received its first 5 from Baldwin (Locobase 6919). The result was a smaller boiler, slightly larger grate and firebox heating surface, and much taller drivers. At 79", the latter put the Wabash in the express passenger big time.

At some later point, the Wabash added 15 sq ft of arch tubes to the direct heating surface, increasing it to 195 sq ft.

Class E3 (Locobase 5350)

Data from table in American Engineering and Railroad Journal (AERJ) July 1904 and confirmed by data from WAB 1907 and WAB 1 - 1917 Locomotive Diagram books supplied in May 2005 by Allen Stanley from his extensive collection.

Note the relatively high drivers even for an Atlantic. Large grate, relatively small boiler compared to other US 4-4-2s of the period. The Wabash later amended the direct heating surface by adding 4 arch tubes comprising 25 sq ft, raising th e total to 202 sq ft.

Class E3s (Locobase 6923)

Data from WAB 1 - 1929 Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive collection. Date for conversion is the first diagram modification date.

As with other superheating conversions, this modification to the E-3 (see Locobase 5350) took advantage of the greater power in dry steam to drop the boiler pressure by 25 psi. At the same time, driver diameter grew by an inch. Both factors combined to lower the calculated tractive effort. Power at speed, however, increased considerably because the Wabash update resulted in almost the same amount of heating surface as was found in the saturated

Class E4 (Locobase 6921)

Data from WAB 1907 and WAB 1 - 1917 Locomotive Diagram books supplied in May 2005 by Allen Stanley from his extensive collection.

It's interesting to compare this set of Atlantics to the E-1 class (Locobase 6918), which Baldwin delivered to the Wabash in 1898. The boiler is bigger as is the grate, but the direct heating surface barely grew at all. Adhesion weight grew by more than 13 tons, only just keeping pace with the increased tractive effort. Perhaps these two classes illustrate better than most comparisons the essential limitations of the 4-4-2 design.

The Wabash later amended the direct heating surface by adding 4 arch tubes comprising 25 sq ft, raising th e total to 202 sq ft. These engines were superheated in the 1920s; see Locobase 6922.

Class E4s (Locobase 6922)

Data from WAB 1907 and WAB 1 - 1929 Locomotive Diagram books supplied in May 2005 by Allen Stanley from his extensive collection. Date given is the first modification date on the diagram.

Superheating the E-4 added quite a bit of power to the basic Atlantic design, perhaps 30% greater power at speed. Although tractive effort dropped as boiler pressure was slightly reduced and driver diameter slightly increased, the decrease in apparent power was more than offset by adding 24 sq ft of arch tubes to the direct heating surface and superheating the steam.

A few of the engines (602, 606, e.g.) were given tenders with cast-steel trucks.

The class's life certainly was extended with three serving through World War II.