One problem with conventional reciprocating steam locomotives is that when the horizontal motion of the pistons is converted into rotary motion of the drive wheels, the torque is not constant throughout the rotation of the wheels. Instead, if the torque were plotted on a graph, it would be represented as a sine-based wave, having high points and low points. The practical result of non-constant torque on drive wheels is a vehicle whose wheels may easily slip when starting.

Another problem with conventional reciprocating steam locomotives is that all of the side rods and valve gear become difficult to balance when the locomotive is traveling at high speeds.

In the 1920s and 1930s, the United States locomotive builders began looking at turbine power like that which is used in steamships and stationary power plants as an alternative to the more traditional reciprocating power. During the next few decades several steam-turbine designs were tested and used. However, none were really a success. Steam turbines make great nautical motors, where the hull of a ship provides a comparatively clean and cushioned environment. Railroad locomotives get dirty while they are running over the road, and freight locomotives also are involved in many low speed high impact collisions coupling up to trains. Passenger locomotives, with a fixed consist were safe from the violence of coupling onto a train, but their higher speeds made them even dirtier than a freight locomotive going thirty or forty miles an hour.

In 1938 General Electric built a pair of steam-turbine-electric locomotives for use on the Union Pacific in an attempt to compete with General Motors passenger diesels. The wheel arrangement of these two locomotives was 2-C+C-2.

The UP ran them on a few test trips and sent them around the country on a publicity tour. However, they were only "operational" for 6 months before returning to GE. Subsequently, they did some work for the GN and NYC during the war but it was deemed that they would be more useful as raw material and were scrapped. These were the only two condensing steam locomotives built and operated in North America and were engineering triumphs but again practical failures.

In 1944, the PRR received a Baldwin-built straight steam turbine where the turbine was geared down and directly connected to the drivers. It looked much more like a regular steam locomotive. The most obvious visual clue that it was not a "normal" steam locomotives was that it had no cylinders nor main rods. It still had side rods connecting the main drivers.

Class S2 number 6200 was built with a new wheel arrangement: 6-8-6. Initially, it was designed to be a 4-8-4. However, because of wartime restrictions on lightweight metals, the locomotive weight required the larger pilot and tender trucks. It had two steam turbines, one large one for forward movement and one small one for backup movements.

Because it did not have reciprocating parts:

• It could travel at higher speeds with smaller (68 inch) drivers.
• It did not "pound" the rails as did other steam locomotives.
• It did not produce the "normal" chuffing sound, instead it produced a loud swoosh sound.

It too was unsuccessful. Once it got up to speed it could outpull anything on the rails at the time (including 6000 HP diesel lashups) but most locomotives didn't spend that much time rocketing across the plains at 100 mph. Below 40 miles per hour, it used an enormous amount of steam and coal. It was used in passenger service between Crestline, OH and Chicago, IL. before being placed in storage in 1949 and later scrapped along with most of the PRR duplex-drive locomotives.

The PRR also had plans for large Loewy-designed class V1 Baldwin steam-turbine-electrics similar to the C&O units but they were canceled before metal was cut.

By 1945 it was obvious that the diesel electric, with its higher low speed tractive effort, cheaper and easier to handle fuel source, and ease of maintenance and higher availability, was here to stay and steam was on the way out. The C&O was a major coal hauler and thought the only way to save steam was to combine the benefits of electrical traction motors to a coal fired steam turbine which generated electricity for the traction motors.

With the help of Baldwin and Westinghouse, the C&O built three steam turbine electrics. Number 500 was built in 1947 and numbers 501 and 502, in early 1948. They had conventional fire-tube boilers mounted backward to regular practice. They were streamlined and looked like nothing else on the rails. They were built for speeds of 100 miles per hour. The only problem was that they were incredibly complex. They spent much more time in the shop than on the rails. The book C&O Power has a few good photos including one with the streamlining removed. It looked like a pipe fitters nightmare. By 1949 they were on the dead line and all three were quietly scrapped in 1950.

The C&O heavily promoted the 500 as the locomotive of the future, and advertised them pulling the soon to be placed in service "Chessie" passenger train. The Chessie was to have four dome cars and one of the lounges had a large warm water aquarium with tropical fish. Yet, the train never made its debut in the summer of 1948. There were strikes at Baldwin, Pullman and Budd in 1947 that delayed the equipment, and testing the 500 was not going well. In February 1948 the B&O launched their own streamliner between Cincinnati and Washington DC. That train stole the Chessie's thunder, and also showed the C&O how minuscule the daytime Cincinnati Washington passenger train market really was.

In 1947, during test runs, the 500 had many service failures. The C&O also found out the tropical fish in the aquarium died due to the train's vibrations. Yet the main problem was the 500. There were many bugs in this long and complicated machine. It was 106 feet long and weighed 856,000 pounds. It had five trucks in a 2-C1-2-C1-B arrangement. Only the first three axles on the eight wheel trucks were powered. The trailing truck was powered, but the leading truck and the one in between the big powered trucks were not powered. That four wheel truck supported the firebox. Coal was carried in a hopper at the nose of the locomotive, a streamlined cowl makes this look like a boiler from ground level, but the fire box was behind the cab and the boiler stretched back toward the tender.

Coal dust fouled the forward traction motors and water dripping from the boiler often short circuited the traction motors on the other two powered trucks. The C&O was never able to get the 500 or her two sisters to go all the way from Washington to Cincinnati in a single day, they always broke down. By June of 1948, the gig was up and the nation's leading hauler of bituminous coal began to rapidly dieselize.

In 1954, the Norfolk & Western received a Baldwin-Lima-Hamilton and Babcock & Wilcox-built a steam-turbine-electric named "Jawn Henry" that looked similar to the C&O attempt. It was shorter, weighed less, and had a Babcock & Wilcox "marine type" water tube boiler (some sources say flash boiler) that operated at 600 psi. and delivered steam at 900 degrees F. It had General Electric traction motors, and rode on four, three axle trucks. All axles were powered so the "Jawn Henry" was a C-C-C-C locomotive.

The name given to this locomotive, "Jawn Henry" was taken from the legendary black construction worker who pitted his hammer and drill against a steam drill and died in the attempt.

Although it could be said that the "Jawn Henry" was superior to the Y6b, it lasted only three years. There were a number of problems with 2300. Most of them were worked out during its short life. Some of these problems included the turbine blades getting out of whack when the locomotive coupled onto a train, fly ash kept getting into the electrical machinery, and problems with the feedwater heater and semi-automated boiler controls. Its major Achilles heel as the water delivery turbine and pump, which had to be constantly replaced due to high operating speed. Although none of these were a "show stopper", the locomotive was mainly used as a "pusher" and was scrapped in 1958. Perhaps if the 2300 was introduced 10 years earlier and did not have to compete against a four-unit "F" consist, it may have had a longer life.