VGN class EL-3A
| VGN EL-3A | |
|---|---|
 Contemporary representation of the EL-3A No. 109 together with a small mine locomotive . The signature reads The Midget and Leviathan "The Dwarf and the Giant".
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| Numbering: | EL-3A 100-109 EL-1A 110-115 sections: EL-1-EL-36 |
| Number: | 10 |
| Manufacturer: | Alco , Westinghouse |
| Year of construction (s): | 1925-1926 |
| Retirement: | 1959 |
| Axis formula : | (1'B) - (B1 ') + (1'B) - (B1') + (1'B) - (B1 ') |
| Gauge : | 1435 mm ( standard gauge ) |
| Length over buffers: | 46,390 mm |
| Service mass: | 583 t |
| Top speed: | 60 km / h |
| Hourly output : | 5150 kW (7000 hp) |
| Starting tractive effort: | 1235 kN |
| Continuous tensile force: | 600 kN at 23 km / h 350 kN at 46 km / h |
| Driving wheel diameter: | 1575 mm |
| Power system : | 11 kV 25 Hz ~ prepared for 22 kV 25 Hz ~ |
| Power transmission: | Catenary |
| Number of traction motors: | 6th |
| Drive: | Rod drive with jackshaft |
The electric locomotives EL-3A of the Virginian Railway (USA) were triple locomotives for 11 kV 25 Hz alternating current for the covering of coal trains on the electrified section Elmore - Roanoke , the main line of the railway. The locomotives were the largest and most powerful in the world when they were delivered.
history
According to Westinghouse , when the electrification of the 215 km long section through the Allegheny Mountains was awarded, the world's largest order for the electrification of a railway line was signed at the time. The contract worth 15 million US dollars includes not only the supply of the entire electrical infrastructure but also the provision of 36 locomotive sections. Of these, 30 were combined into ten triple locomotives of the EL-3A series and 6 were used as single locomotives of the EL-1A series. The individual sections were numbered EL-1 to EL-36.
The first triple locomotive was presented on May 14, 1925 at the Westinghouse plant in Pittsburgh . The electrical operation started on September 14 of the same year on the west ramp of the Allegheny Mountains from Elmore to Clarks Gap , on October 1 to Princeton and on September 16, 1926 continuously to Roanoke.
Two EL-3A locomotives - one at the front and one at the rear of the train - carried 6,000 t trains over the 21 ‰ ramp from Elmore to Clarks Gap at 23 km / h. On the 6 - ‰ - ramp between Whitethorne and Merrimac, the tractor was sufficient to move 9,000 t trains. The electric operation doubled the capacity of the line because the trains could climb the 21 - ‰ - ramp twice as fast as the steam locomotives, which reached only 11 km / h on the same route section with a lighter, only 5500 t heavy train. During the descent, the electric regenerative brake of the locomotives not only reduced the wear and tear of the wheel tires and the consumption of brake pads, but also saved 15,000 MWh of energy per year.
The ten EL-3A handled the entire operation on the electrified route section and replaced 48 large mallet steam locomotives . The locomotives, referred to as squareheads by the staff , were twice as expensive to buy as a steam locomotive of a similar performance class, but required significantly less maintenance than these, so that the additional costs were justified. The steam locomotives could only be used for transporting trains half the time due to the time required for heating up, slagging, turning in the end stations and maintenance work, while the electric locomotives were available for transporting trains over 90% of the time.
The fleet of electric locomotives of the Virginian Railways was only supplemented in 1948 by four double locomotives of the EL-2B series and in 1955 by 12 locomotives of the EL-C series . The EL-3A were in use until electrical operation was discontinued in 1959.
technology
An EL-3A locomotive consisted of three sections that were connected by semi-permanent couplings and could be operated from a driver's cab. The control circuits would also have allowed multiple control of four sections, but this was not used in practice. Each section was operational on its own. The electrical part came from Westinghouse, the car part from Alco . Each section had a locomotive body in box cab design , which, without transferring tractive forces, lay on two bogies, in each of which two driving axles and a leading running axle were arranged.
The drive was carried out by rods with a disposed between the barrel axis and the first driving wheel set jackshaft were connected. This was provided with radially sprung cranks, which were driven by a three-phase asynchronous motor in a Dahlander circuit with a slip ring rotor .
The locomotive was designed as a converter locomotive , in which the single-phase alternating current from the contact line on the locomotive was converted into three-phase alternating current to supply the traction motors with the help of a rotating converter . The converter was as asynchronous - rotary converters , also Spaltumformer called, executed and had a throw-off device.
The current from the overhead line was fed via the pantograph to an oil-cooled main transformer, which reduced the voltage. The transformer's cooling circuit was equipped with a forced circulation system and a forced-air cooler. The converter was connected to the secondary side of the transformer, which converted the single-phase voltage into an unregulated three-phase voltage for the traction motors. The locomotive only had two continuous speed levels, which were achieved by changing the poles of the traction motors. The corresponding speeds were 23 and 46 km / h. The approach was carried out with the aid of a liquid filler connected to the slip ring circuit of the asynchronous motor , in which the level of the electrolyte was controlled by the drive switch .
When traveling downhill, the locomotive switched to regenerative braking without the driver having to do anything and without changing the circuit . Driven by the wheels, the asynchronous motors began to work as generators as soon as their speed exceeded the synchronous speed of the motor, and the electricity generated was fed back into the catenary via the converter. The braking power was just as great as the drive power, so that a train could be kept in a steady state without using the pneumatic brake when traveling downhill.
literature
- EI Staples: The First Virginian Electric Locomotive . In: Railroad and Locomotive Engineering . Vol. 18, No. 6 , p. 157-159 ( archive.org ).
Individual evidence
- ↑ a b c d e f E.I. Staples: The First Virginian Electric Locomotive . In: Railroad and Locomotive Engineering . Vol. 18, No. 6 , p. 156 ( archive.org - left column).
- ^ A b Bonnier Corporation: Is the iron horse doomed? In: Popular Science . Bonnier Corporation, February 1932, p. 132 ( Google Book [accessed June 20, 2016]).
- ^ The Virginian Railway. In: American-Rails.com. Retrieved June 21, 2016 .
- ↑ Kevin EuDaly: The Electric Virginian / Virginians New Electrics meet all requirements . In: The Arrow . Vol. 30, No. 3 , 2014.
- ^ Errata Page to the book "Images of Rail, The Virginian Railway" by Arcadia Publishing. Accessed June 21, 2016 .
- ^ Alfred H. Lovell: Recent development in heavy electric traction . In: The Michigan Technic . March 1924, p. 19-20 ( Google Book [accessed June 20, 2016]).
- ^ The climb to Clark's Gap via the former Virginian Railroad. In: Train of Thoughts. Trains Magazine, April 16, 2013, accessed June 25, 2016 : "[...] a fleet of EL-3As (dubbed Squareheads) [...]"
- ↑ Karl Sachs: Electric Vollbahnlokomotiven: A manual for practice as well as for students . Springer-Verlag, 1928, ISBN 978-3-642-51847-8 , pp. 392–394 ( Google book [accessed on June 19, 2016]): “The first attempts to test the usability of the system […] were […] carried out at the instigation of RE Hellmund. In his experiments, Hellmund used an induction motor with a squirrel cage armature as a phase converter [...]. When started in some way, the machine ran automatically [...]. The first phase converter locomotives, for which the Hellmund experiments provided the basis, were the locomotives supplied by Westinghouse for the 90 km Vivian-Bluefield route of the Norfolk & Western Railway […] […] locomotives […]. […] The 36 1B – B1 locomotives of the Virginian Railway delivered in 1925 are very similar in terms of wheel arrangement, drive disposition and electrical equipment. The three of them are combined into one vehicle. Fig. 397: Basic scheme of a phase converter locomotive with asynchronous phase converter. "
