Camelback locomotive

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The Erie Railroad's L-1 class were the largest camelbacks built, and the only articulated examples.

A camelback locomotive is a type of steam locomotive with the driving cab placed in the middle, astride the boiler. This placement was done to improve driver visibility; camelbacks were fitted with wide fireboxes which would have severely restricted driver visibility from the normal cab location at the rear. Camelbacks were also known as Mother Hubbards or center-cab locomotives.

Development

Early Use

The Baltimore and Ohio Railroad began to look into developing high-powered steam locomotives in the early 1840s, and in 1844 - 1847 built a series of locomotives nicknamed "muddiggers". As with many early B&O locomotives, a spur gear drive was used to connect the main shaft to the driving wheels. The long 0-8-0 wheelbase pushed this connection to the back of the locomotive and caused the floor of the cab to be lifted up above the whole assembly.

Baltimore and Ohio Railroad #217, a type 4-6-0 camelback the Ross Winans, on display at the New York World's Fair on July 23, 1940.

In 1853 Ross Winans, who had designed the "muddiggers", built the first of a series of 0-8-0 camelback locomotives. These had long cabs that ran from the back of the smokebox to the front of the firebox. The firebox itself sloped back on the earliest models; later models had longer "furnaces" which eliminated the slope, but which had a shallow curve from side to side. The firebox did not hang over the wheels, but it was wider than the main part of the boiler and would have obstructed the cab. The fireman worked from a large platform on the tender, and in some cases had a chute to allow him to deliver coal to the front of the grate.

Also in 1853, Samuel Hayes, the Master of Machinery for the railroad, had built a series of camelback 4-6-0 locomotives for passenger service. The layout of the locomotive was roughly the same as for Winans' freight locomotives, except for the addition of the four wheel leading bogie. Copies and variations on these locomotives were built into the 1870s, with the last retirements coming in the 1890s.

The B&O examples burned conventional bituminous coal. The large fireboxes of these locomotives were made obsolete by better boiler design.

The Wootten Firebox

Main article: Wootten firebox
4-6-0 camelback built for the Central Railroad of New Jersey by the Baldwin Locomotive Works.

John E. Wootten developed the Wootten firebox to effectively burn anthracite waste, which was a possible plentiful, cheap source of fuel. Wootten determined that a large, wide firebox would work best. As the successful trailing truck used to support large fireboxes had not yet been developed, Wootten instead mounted his huge firebox above the locomotive's driving wheels. The problem now arose that with a cab floor at the then standard tender deck height, it would be impossible for the locomotive's engineer to see forwards around the firebox shoulders. Instead, a cab for the engineer was placed above and astride the boiler. The fireman, however, remained at the rear with minimal protection from the elements. This gave rise to the unusual shape of the camelbacks.

First Camelbacks

The first camelback, a 4-6-0, was built in early 1877 by the P&R's Reading, Pennsylvania shops. It proved a success; the fuel cost saving was about $2,000 a year (approx. $30,000 now). More were built for many of the railroads operating in the anthracite regions, and some others, of many different wheel arrangements. The largest ones had a 0-8-8-0 arrangement and were the only articulated camelbacks built.

Safety problems

The camelback was not a very safe design for its crew. The engineer was perched above the whirling siderods, vulnerable to swinging and flying metal if anything below should break. The fireman, meanwhile, was alone and exposed to the elements at the rear. The Interstate Commerce Commission banned further construction of camelbacks, but gave exceptions to allow some to be completed. In 1927, further orders were completely prohibited on grounds of safety.

Many camelbacks were converted into end-cab locomotives; the advent of the mechanical stoker and its associated underfloor machinery placed cab floors and tender decks higher, and from that vantage point the engineer could see ahead.

Survivors

Owning railroads

References

ja:キャメルバック式蒸気機関車

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