Push train control
With push-pull train control , the time and effort required to assemble passenger trains in railway operations can be minimized. In addition to the standard passenger coaches, a push-pull train includes a diesel or electric locomotive equipped for push-pull operation and a control car . In rare cases, the process is also used on freight trains .
The engine driver can lead the train from both the locomotive and the control car, whereby the "remote-controlled" motor vehicle from the control car "pushes" the train. This eliminates the need to move the locomotive to the other end of the train at terminal stations or to change locomotives at intermediate stops with a change of direction, especially in head stations . The push-pull train control is mainly used in local and regional transport, but intercity trains also run in push-pull operation.
The German ICE also has driver's cabs on both sides. The trains of the first generation still have two power cars . The trains of the second generation , however, only have a powered locomotive at one end of the train. At the other end of the ICE-2 half-train has a control car, which also makes this type of train a push-pull train.
A technical distinction is also made between analogue and digital push-pull train control.
A distinction is made between direct push-pull train control, in which all functions (drive and brake) are operated from the control car, and indirect push-pull train control. Under the indirect shuttle train is the driver of a running at the head of the train Wendezugbefehlswagen of control commands with the engine telegraph on ships similar device to the locomotive where they the regulator authorized heater quit immediately and must perform. The train brake is also operated with indirect control from the driver's cab of the push-pull train command vehicle.
In 1951, the Deutsche Bundesbahn decided to use indirect push-pull train control in steam mode, as the heater had to remain on the locomotive to operate the fire and also to detect malfunctions typical of steam locomotive operation. When braking was initiated by the train driver seated in the push-pull train command car, the steam supply to the locomotive engine was shut off by a compressed air-operated regulator closing device, so that no drive force could act on the wheels that could have delayed braking. Class 78 , 38.10 , 65 and 23 steam locomotives have been converted for this purpose .
The experiments with electric locomotives (at that time on a converted E 04 locomotive ) appeared to be more promising , since the engine driver could control the locomotive directly. Due to the Second World War, the test program could not be completed despite good results. It was only after the war that push-pull train operation - initially in the area of the German Federal Railroad - could slowly establish itself when locomotives and wagons with the appropriate standard equipment were available.
Conventional push-pull train control (KWS)
In Germany, signals are transmitted in analogue fashion via a 36-pin ( Deutsche Bundesbahn ) or 34-pin ( Deutsche Reichsbahn ) push-pull control cable. The lines transmit individual control commands to the locomotive to be controlled and return status messages. In addition, analog values such as B. Motor current and contact wire voltage or the setpoint for the dynamic brake. Control cars with conventional controls can only be used for operation with steam, diesel or electric locomotives; a change in the type of traction requires the driver's cab to be converted in the workshop, with the exception of the Wittenberger head , where switching a switch is sufficient.
Time division push-pull train control (ZWS)
Back in 1978, got the conventional shuttle train Competition: The developed this year train - pull trains from x-cart along with locomotives of the 111 series used for data transfer between the locomotive and control cars, the time-division shuttle train, in which instructions, messages and values digitally transmitted. The signaling of the CFB occurs via the wires 10 and 11 of every vehicle existing UIC cable (UIC 568). A more common name today is IS line ("information and control line"). 80-bit datagrams are transmitted between the locomotive and the control car with the aid of modems . The locomotives send a datagram with their series identification because the control car has to react differently to different locomotives.
It was not until 1992 that the new double-decker coaches were delivered to a larger extent, going beyond the S-Bahn service in the metropolitan areas . The DABgbuzf 760 type received both the 34-pole and the time-division multiplex control as a temporary solution. Since then, the fields of application have been continuously expanded. Since then, newly acquired locomotives and control cars have generally been equipped with the ZWS, while numerous older locomotives and control cars have been retrofitted with the ZWS. With the exception of a few double-decker control cars of the Reichsbahn design as well as the push-pull trains run with control cars of the Karlsruhe design, the ZWS completely displaced the KWS.
A variant of the ZWS is the time-division multiplexed double traction control (ZDS), which works on the same principle and enables two locomotives to be driven twice over the UIC cable. From this, the time-division multiplex multiple traction control (ZMS) has been developed, which also enables combinations of more than two locomotives and the control of more than one locomotive from the control car. However, their degree of distribution is still quite low.
In order to transmit further commands such as those for side-selective door control, most vehicles have been expanded with frequency-multiplex train control (FMZ). This control transmits the required additional commands on the same wire pair by means of frequency division multiplexing on a carrier .
Push train control via WTB
The control cars of the series 80-33 and 80-73 used in Austria , as well as the Railjet control cars, transmit the data between the locomotive and the control compartment via the train bus ( WTB ) in accordance with the ÖBB remote control concept. The Intercity 2 of Deutsche Bahn AG also uses WTB for push-pull train control. In contrast to the time division multiplex systems, in which only locomotives and / or control cars communicate with each other, all passenger cars carried can optionally participate in bus communication via the WTB. The push-pull train control can thus be expanded to include the processing of diagnostic messages from the individual wagons. The WTB is therefore no longer limited to data transmission for traction control. Furthermore, with the WTB, similar to the ZWS with an additional time-division multiplexed double traction control, multiple control of locomotives is possible in addition to the push-pull train control , which ensures the greatest possible flexibility in train composition.
The WTB telegrams in UIC Leaflet 556 are standardized for international use in passenger trains. The wires 17/18 of the UIC cable are provided for transmission. Alternatively, the data line of the nine-pole Ep line can also be used in accordance with the standardization . A different line can also be used in technically identical sets.
Push train control via MVB
The most modern form is used for the ICE and for the new S-Bahn railcars or new-build diesel multiple units. It is the " multifunctional vehicle bus " (MVB). Datagrams with control signals or sensor data are also transmitted on this serial bus for railway vehicles . Another application of the MVB is its use within individual wagons, while a WTB is used across all wagons.
There are a number of other methods. Locally distributed variants are often used on regional branch and narrow-gauge railways. As with all other procedures, the respective vehicles in a train set must use the same system. Only technically pure vehicles can be controlled among each other.
In Switzerland, the term multiple control is mostly used , although this term goes beyond its pure use as push-pull control.
Use in freight transport
In freight turning trains arrive only in exceptional cases used when trains operate over relatively short distances. In these cases, where the trains do not have to be dismantled into individual wagons at the destination, the system can be worthwhile because it saves you having to move the locomotive frequently when changing direction . For example, push-pull trains ran on the works railway in the Upper Palatinate lignite district , transporting lignite from the opencast mines near Wackersdorf to the nearby Dachelhofen power plant or power plant ash in the opposite direction.
- Multiple control , term for push-pull train control and multiple traction in Switzerland
- Jürgen Ebel: The new steam locomotives of the Deutsche Bundesbahn Vol. 1: Technology and history of the locomotives with tender BR 23 and 10 ; 1984; ISBN 978-3-17-007357-9
- Assignment of a 36-pin push-pull train control cable (page 33) ( Memento from December 29, 2015 in the Internet Archive )