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Not What You Meant?  There are 24 definitions for Bank.  Also try: Banker.

Bank engine

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SZ Taurus pushing a freight train on the grade between Koper and Hrpelje-Kozina. An SZ class 363 is leading the train. July 2007.
SZ Taurus pushing a freight train on the grade between Koper and Hrpelje-Kozina. An SZ class 363 is leading the train. July 2007.

A bank engine (United Kingdom/Australia) or helper engine (North America) is a railway locomotive that is temporarily attached to a train that requires more power or traction to climb a grade (or bank). They are most commonly found in mountain divisions (called "helper districts" in the U.S.), where the ruling grade may demand the use of substantially greater motive power than that required for other grades within the division.

Contents

Application

Bankers or helpers were historically attached at the rear of the train, in which case they also protected against wagons or coaches breaking away from the train and running back downhill. Also, in a pusher role, it was possible for the helper/banker to easily uncouple once the train had crested the grade. Once uncoupled, the engine would return to a siding or stub so as to clear the mainline and get ready for the next train. Since it was not possible to remotely control a steam locomotive, each helper/banker had to have a full crew on board. Careful coordination was required between engine crews to assure that all locomotives were operated in a consistent manner. Standard whistle signals were employed to tell the helper crew when to apply power, drift or brake. A misunderstanding of signals by a pusher locomotive crew could result in a major wreck if the lead locomotive applied brakes while the bank engine was still applying power. The usual result was that the train would experience a violent run-in (an abrupt bunching of train slack), resulting in the derailment of part or all of the train. In modern practice, helpers/bankers are often placed in the middle of the train and are controlled by coded radio signals from the locomotive at the head end of the train, allowing one engineer (driver) to simultaneously control the helper(s) and main consist. This arrangement has the distinct advantage of applying the helper power to only part of the train, thus limiting the maximum drawbar pull applied to the first car of the train to a safe level. The Denver and Rio Grande Western Railroad, in particular, used "swing helpers," which meant the helper locomotives were placed mid-train at a point where they were pushing and pulling an approximately equal amount of tonnage, said location being referred to as the train's "swing point". However, this arrangement requires splitting the train in order to add or remove the bank engine(s) and therefore is not common where bank engines have to be added and removed quickly. In countries where buffers-and-chain couplers are used, bank engines often cannot be added to the front of the train due to the limited strength of the couplers. In the case of standard UIC couplers and a maximum grade of 28‰ (which is common e.g. for lines through the alps), the limit is a train weight of 1400 tons[1]; if a train is heavier, bank engines have to be added in the middle or to the end of the train in order not to exceed the maximum load for any coupler. In the UK, an engine that was temporarily attached to the front of a train to assist with the ascent of an incline was called a pilot locomotive. This differentiated it from the train engine(s) which was provided to power the train to its destination. In Canada or the USA, a train with one or more helper locomotives attached to the head end would be referred to as a "double header," "triple header," etc., depending on the number of helpers/bankers. These terms gradually fell out of general usage as Diesel locomotives replaced steam power. The town of Helper, Utah was named after these engines, as it was where helper engines were kept to assist on the climb to Soldier Summit. Helpers/bankers were most widely used during the age of steam, especially in the American West, where significant grades are common and trains are long. The development of advanced braking systems and Diesel-electric or electric locomotives has eliminated the need for bankers/helpers in all but a few locations.

Examples

The following are locations where bankers are, or were, frequently required:

Australia

New South Wales

Europe

Japan

  • "Senohachi" section (Seno - Hachihommatsu) of Sanyo Main Line - Dedicated EF67 electric locomotives assist heavy freight trains.
  • Usui Passon the Shinetsu Line - The maximum grade of 6.67 percent necessitated the use of helper locomotives on all trains, both uphill and downhill (for added braking ability). A pair of EF63 electric locomotives were connected to the downhill side of every train. This segment was closed after the opening of the Nagano Shinkansen in 1997.

New Zealand

United Kingdom

United States and Canada

Accidents

See also

Notes

External links

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Bank engine from Wíkipedia. ©2006 by Wíkipedia. Licensed under the GNU Free Documentation License. View a list of authors or edit this article.

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