The Norfolk & Western class A consisted of a total of 43 simple articulated locomotives, which were suitable for different types of trains from slow coal trains to passenger trains. The trailing bogie allowed for a very large firebox, generating around 5,400 horsepower even without thermosiphons or water pipes. To reduce friction, roller bearings were installed on all axles, the last five even had roller bearings on the drive and coupling rods. 

The maximum load for slow freight trains on flatter routes was between 13,000 and 14,500 short tons. Express freight trains could be pulled up to 5,200 short tons and passenger trains could reach speeds of 70 mph and more. Because of the large water usage, old tenders were converted to water-only tenders, adding an additional 20,800 gallons to the 22,000 gallon capacity. With a tender and an additional water car, the locomotives weighed 1,233,000 pounds. Their service life ended between 1958 and 1959.

No. 1206 in 1937 in Columbus, Ohio

collection Taylor Rush

Today the number 1218 from construction year 1943 still exists, which was restored between 1985 and 1987. It was then the world's strongest pulling operational steam locomotive. With the termination of the Norfolk & Western steam program, however, it was parked again after only four years and is now waiting to be refurbished again.

In order to be able to accommodate a longer boiler on the Consolidation, the Norfolk & Western chose the 4-8-0 “Twelve-wheeler” wheel arrangement instead of the Mikado. The aim was to achieve a higher adhesive weight because the weight of the firebox was placed on the rear driving axles. Even the firebox was extended to the rear of the cab so that the engineer and fireman were separated from each other. They were nicknamed “Mollies” by the crews.

After 125 class M locomotives, 100 more class M1 locomotives were built. They only differed in the valve gear and the valves. Due to design errors, the M1 was subject to high levels of wear and tear, so it was phased out relatively early. The M was replaced on main lines by the 2-8-8-2 class Y and was used on secondary lines and in switching service until the late 1950s. Only ten had received a superheater. The number 475 is still in use on the Strasburg Railroad today and the 433 also survives.

The last generation in their series of 2-8-8-2 wheel arrangement Mallets, begun in 1910, was built by Norfolk & Western from 1930. While most other North American railroads had long since abandoned real Mallets and introduced ones with simple steam expansion instead the last series still had a compound engine. They were all made in the Roanoke workshops of Norfolk & Western and it all started with the Y4a as a development of the Y4 with an enlarged grate and significantly higher boiler pressure. Some optimizations were made to the internal piping that increased efficiency.

A young boy admires Y6 no. 2127 in May 1955

collection Taylor Rush

The first eight Y4a left the factory in 1930 and still had forged frames. On the ten Y5s from 1931, the frames were cast in one piece. The Y4as were also fitted with the new frames in 1940 and 1941. Also in 1940, 35 Y6s followed, in which the cylinders were now manufactured together with the frame as a cast part and had roller bearings on all axles. These were followed by another 15 Y6as, delivered in 1942.

Y6a no. 2162 (front) and Y6b no. 2200 (rear) in January 1958 at Grundy, Virginia

collection Taylor Rush

Between 1948 and 1952, 30 examples of the Y6b followed, which would become the most modern Mallet locomotives in North America. They featured a larger firebox and a special mechanism that allowed them to run at all speeds with single steam expansion, increasing tractive effort at the expense of efficiency. The front bogie with the low-pressure cylinders was weighed down with several tons of lead to increase the adhesive weight. The diameter of the coupled wheels was one inch larger, and these were also retrofitted to the predecessors. In the last few years of service, the locomotives were equipped with technical aids that increased the starting tractive effort to almost 170,000 pounds or 755 kN.

All in all, the locomotives are considered to be the most powerful, commercially successful steam locomotives ever. Some earlier prototypes could muster even higher starting tractive effort, but the boiler no longer provided sufficient steam as the speed increased. However, the Y4a to Y6b could also haul heavy trains at up to 50 mph and at 25 mph with 13,500 tons on the hook achieved a drawbar power of 5,500 hp. Although this was surpassed by the Big Boy, this was designed for higher speeds and therefore had a lower starting tractive effort than the locomotives described here with single steam expansion. These large Mallets were retired by 1960 and today only Y6a number 2156 survives. It belongs to the Saint Louis Museum of Transportation and is not roadworthy.

To carry heavier express trains, the Norfolk & Western designed the class J, which had a 4-8-4 wheel arrangement and distinctive streamlined casing. It was characterized by a bullet nose, a skyline casing on the top of the boiler and skirting on the running boards. They are considered the most powerful Northerns ever built, surpassing the New York Central's Niagaras. A good compromise between high tractive power and high speeds was chosen with a driver diameter of only 70 inches, a very precise counterbalancing and a very rigid layout of the chassis.

Although the wheel diameter of 70 inches would, according to the rule of thumb, only be sufficient for a top speed of around 70 mph (113 km/h), theoretically they could reach up to 140 mph without causing damage to the locomotive and tracks. In reality, with 15-car trains they reached speeds of around 110 mph (177 km/h). At the same time, stopovers were reduced by the automatic lubrication system, which served 220 points and only had to be refilled every 1,300 miles. 

The first five were built in 1941 and 1942 with streamlined fairing and lightweight coupling rods. Due to the war, the next six had to be built in 1943 without these features. They were only retrofitted after the end of the war. Three more followed in 1950, bringing the total to 14. When the most important express trains were dieselized in 1958, they were used about one additional year in freight service. The 611 was saved from scrapping and has been back in use since its last overhaul in 2015 and is one of the biggest stars among North American steam locomotives.

After the Nickel Plate Road class H-5 of 1917, the next ten H-6a were USRA Light Mikados, delivered by ALCO. In the years 1920 to 1924, Lima delivered the classes H-6b to H-6f, which were virtually identical to each other and totaled 61 units. 15 more, which were again USRA Light Mikados, came to the NKP in 1923 via the acquisition of the Lake Erie & Western and became the class H-6o.

Over time, individual Mikados were equipped with mechanical stokers and larger tenders. The fireboxes were also changed. For most of them, the service life ended in the forties. Today 587, 624 and 639 are preserved, with the 587 having been operational for a longer period since 1988.

S-2 No. 765 in May 2013

Ron Shawley

The C&O T-1 class with the 2-10-4 wheel arrangement was developed from the Erie 2-8-4. Lima reduced this again by one driving axle and thus created the class S of the NKP. In the years between 1934 and 1949, a total of 80 class S, S-1, S-2 and S-3 locomotives were built, which shone with exceptional performance and pulled fast freight trains. They produced around 4,500 hp and were designed for speeds of 70 mph. They were scrapped between 1957 and 1964. Today there are still six preserved. The best known is the 765, which runs fully booked special trips on a regular basis. The 779, which still exists today, was Lima's last steam locomotive built in 1949.

The first 2-6-6-4 articulated locomotive ever built was the class J-1 of the Pittsburgh & West Virginia. They were created in 1934 by Baldwin to surpass the power of existing 2-6-6-2 locomotives. In contrast to later 2-6-6-4s, the P&WV didn't need them for high power at high speed, but for heavy medium-speed freight trains in hilly terrain.

The three locomotives of class J-1 had drivers of only 63 inches (1,600 mm) and a two-axle booster in the tender that added an additional 16,000 pounds of starting tractive effort. The trailing truck allowed a Belpaire firebox with 499 square feet (46.4 m²) of heating surface and a grate of 102.3 square feet (9.5 m²).

Later the booster in the tender was removed and the drivers were enlarged to 64 inches. In 1937, four additional J-2 class locomotives were built without boosters. Even though they were not built for high speeds, they are reported to have reached speeds of 50 or 60 mph. Their retirement took place in 1953.