SBB-CFF-FFS Am 4/6 1101

The On 4/6 1101 was a gas turbine locomotive of the SBB. It was built by the BBC in 1938 and handed over to the SBB for trial operation on the non-electrified lines. Later it was converted into an electric locomotive and three system used from 1961 as Ae 4/6 III 10851 in the Geneva area.

  • 5.1 design
  • 5.2 Operation

Prehistory

The BBC had built in 1938 a gas turbine system for a 4000 kW emergency diesel generator for the city of Neuchâtel. To check whether the gas turbine for locomotives can be used, suggested the BBC before, a gas turbine engine with a power of 2200 hp (1618 kW) to build and electric power transmission.

The SBB gave the BBC the opportunity to test the gas turbine in railway operations. A top speed of 110 km / h were determined. For a six-axle locomotive, it was not possible to install a system with a capacity of more than 2200 hp (1618 kW), otherwise the maximum operating weight of 92 tonnes with a full fuel tank would have been ( 5.5 tons ) exceeded. The SBB had refused not only testing, but also the acquisition of the locomotive in this case. On the other hand, the SBB pledged to take the locomotive in good working condition. Under the direction of the BBC, the locomotive using the SLM was built for the mechanical part on their own account.

Technology

Construction

The locomotive was based as far as possible on proven technology, in order not to compromise with errors in components that had nothing to do with the gas turbine project. The electric power transmission was chosen because the technology had proven itself in interaction with diesel engines. It allowed to drive any number of axes, which (compared to steam and diesel locomotives that time ) was an important factor because of the large power per weight. Whereas, moreover, hydraulic drives were not in this performance category ( over 400 hp) tested.

The gas turbine consisting of a compressor, a combustor and the turbine itself, the compressor took about 6000 horsepower to compress the air and then to convey into the combustion chamber ( air pressures between 700 kPa to 2.1 MPa, depending on the speed of the turbine ), wherein the fuel ( fuel oil) has been burned, leading to an expansion of the gases, which in turn meet the turbine at a temperature of 500-600 ° C and there developed around 8000 hp. The exhaust gases then flow through a heat exchanger, the prewarmed fresh air before they were ejected through the roof. The remaining approximately 2,000 horsepower could be used to drive the locomotive. The turbine reaching a maximum speed of 5200 min-1, the idling rotational number was 2800 min -1. The rotational speed of the generator has been reduced by a gear 812 min-1 at full load.

Efficiency

Measurements showed that the efficiency from idle to medium load (1000 hp) continuously from 0% rose to 15%, reaching its maximum of 18% at 1700 hp and then fell again to 16 % at 2200 hp (all figures without electrical losses ). The efficiency was low, compared with former diesel technology, which was an important factor that the technology is not penetrated.

Start the engine

First, an auxiliary diesel engine was started with power from a battery. This was associated with an auxiliary generator, which generated electricity for starting the turbine. Thus was mounted on the turbine main generator, which is now running as an electric motor up to speed. This process took about 4 minutes after which the combustion was ignited and turbine operation from then itself While the speed continues to increase, the performance of the auxiliary diesel engine could be used to the engine at low speed (10 km / h) before the train to maneuver. After another four minutes, the idle speed was (430 min-1 on the generator ) is reached and ready for the locomotive.

Increase performance

To increase the power output of the locomotive, the engineer was able to turn on its power controller, which caused the following procedure:

  • More fuel was injected
  • The speed regulator is set to a higher target rotational speed
  • The overload protection noticed an overload situation (speed below the set speed ) and switched electrical load of the turbine from (!)

Since the load was now smaller and more fuel was injected, the speed increased rapidly (up to 812/min on the generator at full load ), and once the target speed was reached, the load was increased again until a new balance between the power output of the turbine and Power consumption of the traction motors was achieved.

To reduce the load, the same operation took place in the reverse order.

Brakes

In order for brake applications do not need to use the air brakes ( wear and risk of overheating ), alternative braking systems an advantage. Since the compressor need to 6000 HP, it was intended to be produced, the driving motors of electricity, which was in turn used to drive the turbine, wherein the power is converted by the compressor heat. The fuel supply was able to be turned off. It is unclear whether the necessary installations were ever made.

If the engineer has increased the performance of late ( eg in a gradient instead of before), the speed increased to possibly not fast enough, which led to too much fuel burned, while too little air for cooling the turbine available stood. In such a situation the overheating of the turbine to the engineer was displayed with a warning lamp. If he did not respond, was according to a further increase in temperature interrupted fuel supply to 30 ° C.

For the case that the load is suddenly dropped on the turbine (for example, due to blown fuses), a safety device was available which reduced the intake of air. This in turn resulted in overheating of the turbine, which in turn was the disconnection of the fuel supply to the sequence.

If the temperature in the combustion chamber was too low, tried the controller to fire the turbine again; if this is not achieved within 5 seconds, the fuel supply is interrupted.

Control logic

The complex control logic was completely rebuilt in oil circuits. All control inputs ( tachometer, power controller, ...) were arranged as valves or pumps so that they influenced the flow of oil and suitable actuators (piston) prepares an necessary control operations.

Operation

The locomotive was on September 5, 1941 to take the maiden voyage under the wheels and has subsequently made ​​sample and test drives. The trial operation had to be interrupted again and again because of wartime fuel shortages. The results of trial operation convinced the leaders, so that the SBB on October 1, 1944, the locomotive officially took over.

Because it lacked in Switzerland in appropriate applications, the locomotive from 1945 to 1946 the SNCF was borrowed. Prior to the express trains on the routes from Basel to Strasbourg and to Chaumont the locomotive provided evidence of serviceability. Subsequently, the locomotive was reinstated in Switzerland.

From 20 June to 2 November 1950, the On 4/6 leased to the DB. She drove from Bw Treuchtlingen in the roster of the series 01, it was said to be superior especially on inclines.

In 1954 the locomotive was parked with serious damage. On an expensive repair of the turbine has been omitted. Reasons were the poor efficiency and the lack of non-electrified lines in the rail network of the SBB.

Up to this point, the gas turbine engine had 410,000 miles. Although the operation was successful, the hope of export orders were not fulfilled for the BBC. A general introduction of gas turbine engines for the SBB was never planned.

The gas turbine locomotive was rebuilt from 1958 to 1961 in the electric three -system locomotive Ae 4/6 III 10851. The conversion should have experience for the construction of the then planned four power - TEE trains SBB RAe TEE II and amplify the only of the two SBB BDe 4/4 II existing DC Park of Geneva- La Plaine.

Construction

The engine received a new box with the same cabs as SBB Ae 6 / 6th The Lokomotiv frame and bogies together with the DC motors and the gears was taken over by the gas turbine locomotive.

The electrical equipment was mounted similarly to the previous gas turbine group on a common carrier, which could be installed and removed through the open roof.

On the roof there were two pantographs. One was used on the SNCF direct current lines (1500 V ), the other on the SBB lines ( 15 kV, 16 2/ 3 Hz) and the SNCF AC lines (25 kV, 50 Hz).

On the SBB network and SNCF AC mains electricity flowed into the transformer, where the voltage was lowered. Subsequently, the alternating current is converted into a silicon controlled rectifier and is supplied to the four DC motors. On the SNCF DC power the traction motors were fed directly from the contact wire four starting resistors to the traction motors.

Operation

The configuration and the conversion took more time than expected. Only in 1961 was the three-flow locomotive to be delivered. At the same time, the four current - TEE trains were delivered, so that the Ae 4/6 III its leadership could not play anymore. After sea trials on French DC and AC lines the traction unit was put into operation.

The three current locomotive was allocated to the depot and got Genève transfer trains in the Geneva area. At the same time it served as a reserve train for the route Geneva - La Plaine.

The transformer was replaced after a serious injury in 1976 through ballast so that the locomotive was used only below 1500 V DC. It served as a replacement locomotive for BDe 4/4 II commuter trains. In 1978 the locomotive was scrapped and fault-prone canceled.

Source

  • Hans Schneeberger: The electric and diesel locomotives of the SBB, Volume I: 1904-1955 model years; Mini rex AG, Lucerne; 1995; ISBN 3-907014-07-3
  • Franz Eberhard: SBB gas turbine locomotive on 4/6 1101 Loki Special No. 13, ISBN 3-85738-059-4
  • Peter will: Locomotives of Switzerland, standard gauge locomotives. Orell Füssli Verlag, Zurich 1972

Further reading

  • Ad. Meyer: The first gas turbine locomotive. Swiss Bauzeitung, Volume 119 (1942), Issue 20 (Part 1 ) ( retro.seals.ch, PDF 3.1 MB) Swiss Bauzeitung, Volume 119 (1942), Issue 21 (Part 2 ) ( retro.seals.ch, PDF 1.3 MB)
  • Ad. Brunner: Read the article: the first gas turbine locomotive: a response. Swiss Bauzeitung, Volume 120 (1942), Issue 7, page 78f. ( retro.seals.ch )
  • Jean Claude Maire: The electric and diesel locomotives of Swiss railways, locomotives of the Swiss Federal Railways ( SBB)
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