# Norfolk and Western Y6, Y6a and Y6b classes

The Norfolk and Western classes Y6, Y6a and Y6b were classes of 2-8-8-2 "Mallet" articulated steam locomotives, with a total of 81 locomotives built for the Norfolk and Western Railway (N&W) between 1936 and 1952.

## Classes Y6 and Y6a
### Development, construction and design

Throughout the 1930s, the N&W's mechanical engineering team explored numerous ways to refine the Y series 2-8-8-2 compound Mallets, since the public demand for coal was increasing, despite the effects of the Great Depression. In 1930 and 1931, the N&W turned out their Y5 class 2-8-8-2's (Nos. 2090–2109) from their East End Shops in Roanoke, Virginia. The Y5s were step-up designs of the previous Y4 class locomotives, which, in turn, were copies of the United States Railroad Administration's (USRA) 2-8-8-2 design, but the Y5s were developed to the point they were considered exclusive N&W designs.
The N&W quickly decided to further develop the Y5 design to improve it, so from September 1936 to November 1940, they turned out thirty-five locomotives of the Y6 class (Nos. 2120–2154). The Y6s shared identical specifications to the Y5s, but with major design changes for improved efficiency; they were built with cast steel frames connected by a pin hinge; outside frame bearings on their pilot and trailing trucks; roller bearings for all the wheel journals; and automatic lubricators. The Y5s would later be rebuilt with most of these modifications.
The Y6s were also designed with 57-inch (1,400 mm) diameter driving wheels—which were later increased to 58 inches (1,500 mm) by thickening the tires—and an operating boiler pressure of 300 psi (2.1 MPa). They were capable of producing a tractive effort of 152,200 lbf (677.02 kN) with simple expansion and 126,838 lbf (564.20 kN) with compound expansion, and when traveling at 25 miles per hour (40 km/h), they were rated at 5,500 horsepower (4,100 kW). Their water bottom tenders held a capacity of 26 short tons (52,000 lb) of coal and 22,000 US gallons (83,000 L) of water.
Since they were equipped with roller bearings and automatic lubricators, the amount of time and expense required to maintain a Y6 was akin to the way diesel locomotives were maintained. In 1942, the N&W decided to build sixteen more Mallets (Nos. 2155–2170), since the Y6s proved to be so reliable, and military traffic from World War II was rapidly increasing. The new Mallets were classified as Y6as, since they were built with some different features from their predecessors; they were equipped with an improved Worthington BL-2 type feedwater heater and an HT type standard stoker; and certain parts were fabricated out of alternative materials, instead of steel, to abide with wartime restrictions.
The Y6as, along with the Y5s and Y6s, were assigned as all-purpose locomotives and operated all across the N&W system; they pulled drag-speed coal trains out of the Blue Ridge Mountains; they pulled merchandise freight trains; they operated as mine-shifters on branch lines; they served as switchers and humpers in yards; and they pushed heavy trains up steep grades.

### Revenue service

One assignment the Y6as received was to haul 6,600-short-ton (6,000 t; 5,900-long-ton) coal trains westbound out of Cedar Bluff, and over the N&W's Dry Fork Branch into Iaeger, West Virginia, where they would then haul 14,500-short-ton (13,200 t; 12,900-long-ton) coal trains into Williamson and Portsmouth, Ohio. From there, the Mallets would either haul 13,500-short-ton (12,200 t; 12,100-long-ton) trains up the Scioto Division to Columbus, or haul 6,800-short-ton (6,200 t; 6,100-long-ton) trains to Cincinnati.
The Y6as were also assigned to haul 3,600-short-ton (3,300 t; 3,200-long-ton) coal trains eastbound from Cedar Bluff to Bluefield, where the trains would be increased to 10,300 short tons (9,300 t; 9,200 long tons), and then the Mallets would haul them to Roanoke. From there, the trains would be decreased to 8,000 short tons (7,300 t; 7,100 long tons) and hauled through the Norfolk Division eastbound to Crewe, where a Z1 class 2-6-6-2—which would later be succeeded by a Y3 class 2-8-8-2 on this route—would take it to Lambert's Point near Norfolk.
After World War II, the Y6 and Y6a class, along with the Y3s and class As, were permitted to haul 14,500-short-ton (13,200 t; 12,900-long-ton) coal trains on the Crewe—Lambert's Point route, unassisted. Most of the N&W's routes consisted of multiple steep grades, where the amount of cars a Y6a was allowed to pull was limited, and a pusher was required for assistance.
In 1955 and 1956, after the N&W realized the economic challenges of keeping an all-steam roster, the railway decided to order some RS-11 locomotives from ALCO and GP9s from EMD to dieselize two of their eastern divisions. No. 2156 and some of the other Y6as were reassigned to operate solely as mine-shifters in coal fields. In early April 1958, Stuart T. Saunders succeeded Robert H. Smith as president of the N&W, and the former made the decision to completely dieselize the N&W railway, with several additional GP9s quickly being ordered.

## Class Y6b
### Development, construction and design

Throughout the 1920s and 1930s, the Norfolk and Western Railway (N&W) was looking into adding stronger steam locomotives to their roster, since the coal industry was booming, and they wanted to operate longer coal trains out of the Blue Ridge Mountains. The Railway's mechanical engineering team was working to refine the company's Y series 2-8-8-2 compound Mallets, despite the concept having been phased out on most other railroads, in favor of simple articulated designs. In 1930 and 1931, the N&W's East End Shops in Roanoke, Virginia, turned out their Y5 class locomotives (Nos. 2090–2109).
The Y5's were the N&W's most powerful locomotives at the time, being rated at 5,500 horsepower (4,100 kW), and they were able to produce a tractive effort of 152,200 lbf (677.02 kN) with simple expansion and 126,838 lbf (564.20 kN) with compound expansion. Between 1936 and 1940, locomotives of the Y6 class (Nos. 2120–2154) were built, and they shared identical specifications to the Y5's, but they were built with newer features for improved efficiency. In 1942, the Y6a locomotives (Nos. 2155–2170) were built, and they were classified as such, since certain materials were altered for the World War II effort.

### Revenue service

After World War II ended, the N&W decided to construct a bypass grade in their Bluefield Division, to discontinue their electrified section there, resulting in their electric locomotives being retired. The end of their electrification, along with the post-war growth for the coal industry, encouraged the N&W to add more Mallets to their roster, and the Railway's mechanical engineering team made multiple upgrades to the existing Y6 design.

### Steam versus diesel tests, upgrades, and controversies

Coal traffic was N&W's largest source of revenue, and it had arguably the most modern and efficient steam locomotives of any major U.S. railroad. Accordingly, N&W resisted conversion from coal-burning steam locomotives to oil-burning diesels longer than most. In 1952, N&W tested its A-class and Y6b-class locomotives against a four-unit Electro-Motive Division F7 diesel set. The tests indicated that fuel costs and similar items were roughly the same, and the test was considered a tie. However, diesels eventually won out for lower maintenance and other operational costs.
Retrospective analyses of these tests have led to suggestions that diesel locomotive builder EMD and N&W cheated in the competition by using locomotives with secret modifications unsuited for daily work. However, the greater weight of evidence and analysis indicates that N&W did not cheat on these tests, and that the only improvements were the ones N&W publicized and later incorporated into many locomotives. Also, the major participants in this debate all appear to agree that N&W did ultimately modify most of its Y5, Y6, Y6a, and Y6b locomotives with a new "intercepting/reducing valve" and ballast on the front engine, which increased their tractive effort.

### Excursion service and scrapping

On July 11, 1959, No. 2174 was tasked to haul an eighteen-car Farewell to Steam excursion on the N&W mainline alongside 2-6-6-4 A class locomotive No. 1240. No. 1240 pulled the excursion from Roanoke, Virginia to Bluefield, West Virginia, where the train was transferred to No. 2174. The Y6b pulled it through the N&W's Pocahontas Division to Iaeger, and then it traveled over the Dry Fork Branch to Cedar Bluff. No. 2174 returned the excursion to Bluefield, and then No. 1240 returned the train to Roanoke.
Following the excursion, No. 2174 was sold to the United Iron & Metal Company, and the locomotive was stored in their scrapyard in Roanoke, along with fellow Y6b No. 2189 and Y6 No. 2143. The rest of the Y6b class was scrapped, between 1958 and 1961. The United Iron hadn't prioritized the scrapping of the three Mallets, since they had already scrapped multiple other locomotives. By 1971, No. 2189 was scrapped, and No. 2174 and the tender-lacking No. 2143 remained in a corner of the company's yard.
During 1975, some local preservationists, including the Roanoke Chapter of the National Railway Historical Society (NRHS), made an attempt to acquire No. 2174. The Roanoke Chapter made a commitment to raise $1,000 to cosmetically restore the Y6b, but they did not have enough time to raise $50,000—the locomotive's scrap value—to purchase the locomotive. Also in 1975, United Iron was purchased by the British-based Bird International Company, and due to a slump in the steel industry at the time, the company ordered for Nos. 2143 and 2174 to be dismantled. In January 1976, No. 2143 was scrapped, and the following month, on February 11, the scrapping process on No. 2174 began. This decision stirred controversy among local railfans, including retired N&W employees who had operated Mallets in revenue service.

## Accidents and Incidents

* On September 26, 1950, Y6b No. 2188 was operating on a freight run when it derailed, flipped over and rolled down an embankment at Alnwick, West Virginia.
* On December 15, 1955, Y6 No. 2153 was on a train run when it suffered a crown sheet failure and an ensuing catastrophic boiler explosion, which destroyed the cab of the locomotive as well as blasting the smokebox door off its hinges. This occurred in Wytheville, Virginia.

## Preservation

Only one of the Y6a's, No. 2156, has been preserved. In July 1959, after No. 2156 was retired from service, the N&W donated the Y6a to the National Museum of Transportation (MoT) in Kirkwood, Missouri, with Stuart Saunders personally presenting it at a dedication ceremony. The locomotive was then left on outdoor static display.
An attempt was made to preserve Y6b no. 2174 during 1975, but due to poor timing, No. 2174 and Y6 no. 2143 were scrapped in 1976.