130 mph With Three-Phase Power in 1903

Test vehicle "A", the one using AEG electrical equipment after its world record run of 130.5 mph (210 km/h). Source: Eisenbahn Magazin, November 1983.

Electric locomotives and similarly powered railcars have always fascinated me. Even though electric propulsion systems for locomotives came along much later than steam power for railroads, it quickly became apparent that the former had a far brighter future. Experimentation with electric propulsion systems was worldwide. Credit for the first electric locomotive goes to a tiny, almost toylike, machine built by Werner von Siemens who demonstrated it in May 1879 at a Berlin Trade Fair. Using 150 volts direct current, the 5 hp (3.75 kW) engine was able to reach 8 mph (13 km/h).

After that progress came rapidly and by 1901 some pretty serious experimenting was under way. The more immediate limitations of DC were recognized and alternating current (AC) was already in use, but even single phase AC has limitations. Thus, in 1899, the two German electrical firms of Siemens & Halske and Allgemeine Elektrizitäts Gesellschaft (AEG) formed, with the support of the Prussian government and various banks, a consortium called Studiengesellschaft für Elektrische Schnellbahnen (St.E.S.) [Study Group for High Speed Electric Railways]. To demonstrate what could be done with electric propulsion, the St.E.S. set out the following requirements:

1 – About 50 seats.

2 – Suitable for mainline service.

3 – Maximum speed between 124 and 155 mph (200 and 250 km/h).

4 – 16-ton maximum axle load.

5 – Two 3-axle trucks with middle axle carrying weight only and both outer axles motorized.

6 – Four motors producing between 250 and 750 hp (186 and 560 kW).

7 – Necessary train and auxiliary braking systems.

8 – Current collection from a catenary erected at one side of the track.

9 – Power between 10 and 12 kV to be reduced onboard the railcar to a suitable voltage.

The contract to build two railcars was awarded to the Cologne railroad equipment manufacturer of van der Zypen & Charlier with AEG and Siemens & Halske providing the electrical systems. The AEG car was designated as vehicle "A" and the Siemens & Halske one was vehicle "S". The finished railcars were also to be capable of pulling three additional coaches.

The group obtained the right to use the Zossen to Marienfelde 14.5 mile (23 km) stretch (see map) of the Prussian military railroad connecting Schöneberg Military Station in Berlin with the Jüterbog Military Station southwest of Berlin. They erected a triple high voltage catenary (3-phase) system by the side of the track. The first wire was at a height of 18 ft (5.5 m) and the third one was 24.6 ft (7.5 m) with the second one in the middle. Voltage varied from 6 to 14 kV at frequencies between 25 and 50 Hz, depending on what speed the test vehicles were to run at.

In retrospect, the choice of a three-phase system in 1899 certainly raised some eyebrows. Everything about the choice raised questions, some of which could not be answered. For example, with a triple catenary system contacted on the side with triple pantographs, what do you do when you come to a turnout or a crossover? The matter of changing the speed of a 3-phase motor is no small matter. Yes, it was possible to do it at that time but it was complex and costly unlike today’s thyristor controls. Still, the St.E.S. proceeded.

Both test vehicles were constructed along the same lines. A wood-clad steel framework similar to that of early aircraft was used. At each end there were large driver compartment offering excellent visibility. Each railcar featured two large sections to accommodate 25 passengers each in 1^st and 2^nd class comfort. Passengers had an unobstructed view of the driver’s cabin. The windows were sealed with fresh air entering through the small windows in the clerestory roof structure. The coach body sat rigidly on the truck with its pivot, but the springing was carried out between the bogie frame and axles by leaf and coil springs. There were also two large air ducts in the roof to guide air to the air-cooled high voltage transformers. With the good cooling provided by this system, it was possible to use somewhat lighter transformers. Each transformer weighed 13,558 lb (6,150 kg) and the two motors weighed 17,967 lb (8,150 kg).

The AEG vehicle had a 68.2 ft (20,800 mm)-long body and a truck center center-to-center length of 43.6 ft (13,300 mm); whereby the truck wheelbase was 12.46 ft (3,800 mm) and the wheel diameter was 49.2 in. (1,250 mm), a measurement that has more or less become standard now.

Operational safety was considered an essential part of the design, since experience with such high voltages and speeds was completely lacking. All high-voltage components were so laid out that neither crew nor passengers could get into contact with any part under power. Such parts were positioned under the vehicle or in the hollow roof space. All switch-gear was pneumatically-operated to avoid bringing high-tension cables to the driver's cab.

The pantographs were certainly the most distinguishing feature of the experimental rail cars. AEG and Siemens & Halske chose considerably different approaches to mounting the six pantographs. In each case, there were two sets of three each. The centerline, i.e., the point of contact with the first (lowest) catenary wire was, was 18 ft (5.5 m) above the top of the rails. The second one contacted the catenary 21.3 ft (6,500 mm) above rail level and the third one was 24.6 ft (7,500 mm) above rail level. A system of springs ensured good contact with the catenary wires. So much for commonality. On the "A" vehicle the individual pantographs were mounted in line, i.e., sequentially. On the "S" vehicle three pantographs were mounted on a heavy duty vertical pole. Both systems had to be modified during the trial runs to better accommodate wind forces and reduce spark formation.

The entire electrical system was divided into two parts so that failure of any one part of the equipment could not prevent the other half from continuing to function. The two transformers, with turn ratios of 12,000: 435, were protected by fuses and connected to the catenary wires by means of an oil-switch. One transformer supplied power to two three-phase motors. The motors operated on 1,150 to 1,850-volts. Variation in current was achieved through star-delta connection as well as through resistors.

The resistors were rather unique. They consisted of large copper plates immersed in a continuously circulating soda (sodium carbonate) solution. Raising or lowering the copper plates changed the resistance of the circuit. The engine driver had a means of doing this. The intent was also to use these novel resistors for rheostatic braking but this application did not prove satisfactory.

The electric motors were axle-mounted without gear transmission and had a maximum speed of 900 rpm. The 28 resistors were positioned at the side and operated by a rack-wheel. The driver's cab contained the necessary speedometer, voltmeter, ammeter and other controls.

The AEG railcar and had flat front faces. The main differences from the Siemens and Halske design were as follows. The motors were not positioned on the axles but were placed on hollow shafts surrounding the axles and were vertically sprung. Power transmission was carried out by leaf springs from the hollow shafts to the wheels. This design allowed for smaller but more complex motors. The starter was of the liquid type with a soda solution as coolant and a copper tube cooler. This liquid starter permitted an even insertion and cutting-out of resistors. Control of the vehicle was carried out from the driver's cab by mechanical devices that operated the contactor gear mounted under the floor.

Weights were as follows: electrical systems, 42.5 tons; mechanical part, 48 tons; and load, 4 tons, giving a total weight of 94.5 tons.

Progress was rapid with both test vehicles being virtually the same. The first tests took place in September 1901. Voltage was in the 6 to 8 kV range and frequencies ranging from 25 to 30 Hz. Speeds ranged between 62 and 84 mph (100 and 135 km/h). Power output was between 1,340 and 1,475 hp (1,000 and 1,100 kW). An early goal was to determine air resistance, braking distances, finding the right braking pressure and the effect of high speeds on the roadbed.

The existing track consisted of 65 lb/yard (32.5 kg/m) rail in 26 ft (8 m) sections mounted on steel ties resting in sand and gravel ballast. This proved very inadequate. The swaying and pitching was actually quite alarming and soon a derailment occurred at 100 mph (160 km/h). This temporarily stopped the trials. This led to increasing the wheelbase of the vehicle’s trucks from 149.6 in. (3,800 mm) to 197 in. (5,000 mm) to improve stability. By 1903, military personnel working day and night rebuilt the track with heavier rail, better ties and ballast. Rails 39 ft (12 m) long and weighing 82.5 lb/yard (41 kg/m) and with ties spaced 26 in. (66 cm) center-to-center. Deeper ballasting was also used. The minimum curve was eased to 6,560 ft (2000 m).

Trials were resumed in September 1903. Braking test showed that from 112 mph (180 km/h) a distance of 4,600 ft (1,400 m) was needed and this required 55 seconds. Further, the operating voltage was set at 14 kV and a frequency of 50 Hz.

On October 23 test vehicle "S" recorded 128.4 mph (206.7 km/h) within 6 minutes from starting and a distance of 8.9 miles. Five days later, vehicle "A" achieved the following shortly after 9 AM..

9:05 depart Marienfelde

9:09 passed through Mahlow station at 112 mph (180 km/h)

9:10 reached 124.2 mph (200 km/h) using 2,800 hp (2,100 kW)

9:11 + 15 sec reached 130.6 mph (210.2 km/h) after 8.4 miles (13.5 km) shortly before the Rangsdorf station and then reduced speed to 100 mph (162 km/h).

9:16 arrived in Zossen.

This was a world record that was only broken in 1931 by Kruckenberg’s Rail Zeppelin and again in 1954 by a French electric locomotive. The St.E.S. continued the tests until November 1903. Even though test vehicles "A" and "S" broke the 124 mph (200 km/h) barrier, this was not the primary objective of these tests and evaluations. Coupled with a Prussian (KPEV) six-axle sleeping car, which unfortunately derailed at 108 mph (174 km/h), the intent was to evaluate some elementary attempts at streamlining the experimental railcars. Addition of the streamlining resulted in an 8% reduction in the power needed to achieve 112 mph (180 km/h). Another thing that was learned was that the addition of "trailers" to the railcars did not really affect air resistance of the railcar. All in all, the performance differences between the "A" and "S" vehicles was very minimal. By the end of November 1903, the St.E.S. ended the tests and issued their reports. Writing some 30 years later, Dr. Walter Reichel, the chief engineer on the project, commented, "It is probable that 143 mph (230 km/h) could have been reached had not caution weighed a thirst for knowledge."

The St.E.S. was very satisfied with what was learned from these tests and undoubtedly laid the foundations for future high speed electric lines throughout much of Germany. The experiments showed clearly that electric traction was capable of achieving 124 mph (200km/h) safely; obviously, the experiments were far ahead of their time and it took 50 to 60 years until the lessons learned from these tests were put to practical use. Practical application of 3-phase technology, however, did not become reality until the advent of the BR 120 multi-purpose locomotive.

Specifications

"Mit Drehstrom über 210 km/h," Christian Tietze, Eisenbahn Magazin, November 1983, p. 50

"Drehstrom Weltrekord Triebwagen von 1903," Eisenbahn Magazin, November 1983, p. 56.

"A History of the Electric Locomotive," Vol 2, F.J.G. Haut, A.S. Barnes & Company, 1981, ISBN 0-498-02466-0

"The Great Book of Trains," Brian Hollingsworth and Arthur Cook, Salamander Books, Ltd., 1987, ISBN 0-517-64515-7.