Main air receiver line
A main air reservoir line (HBL or HB) or feed line is a compressed air line installed in rail vehicles in addition to the main air line (HLL or HL) . In the case of locomotives , it is present in all newer vehicles , in the case of wagons only in passenger coaches and a few freight wagons . It is under a pressure of a maximum of 10 bar (overpressure) and is a supply line for the compressed air-operated units of a rail vehicle .
Such units operated with compressed air are for example
- the air suspension of passenger coaches
- the driver's brake valve of a control car
- the magnetic rail brake
- further secondary consumers such as the door locking device.
The main air reservoir line is fed from the main air reservoir of the locomotive. The air compressor , the compressor of a rail vehicle , keeps the pressure in the main air reservoir between 8.5 and 10 bar. If the pressure falls below the minimum pressure of 8.5 bar, the air compressor is automatically activated and operated until the maximum pressure of 10 bar is reached. In older traction vehicles, the pressure values are 6.5 and 8 bar. The driver can follow and check this process in the driver's cab on a manometer in the main air reservoir.
The presence of a continuous main air receiver line is a prerequisite for push-pull train operation with control cars . The air compressor of the locomotive running at the end of the train supplies the driver's brake valve of the control car.
In passenger coaches with magnetic rail brakes , the pressure from the main air reservoir line is required to lower the brake magnets. Since this is safety-relevant, the continuity of the main air reservoir line must be checked on all trains with magnetic rail brakes before the start of the journey and after every change in the vehicle sequence. For this purpose, an operator at the end of the last car of the train opens a shut-off valve on the main air reservoir line as part of the brake test . If the train driver detects a pressure drop on the pressure gauge of the main air reservoir, proof of patency is provided. If this is not the case, then not all relevant air shut-off valves (except for the one at the end of the last carriage) were opened properly during coupling or there is damage to the main air receiver line.
Another important application is the supply of pneumatic service equipment , such as door locking devices or toilet systems in passenger trains.
In the case of freight trains, the main air reservoir line is used in a few individual cases to quickly replenish the air supply of the individual wagons that is used up after braking.
To distinguish between main air and main air tank lines during coupling, the two connections of the main air tank line are attached to the outside and the two connections of the main air line are attached to the inside. In addition, cross-shaped ribs are cast on the coupling head of the main air reservoir line. In addition, the coupling heads of the main air and main air reservoir lines are mirror-inverted so that they cannot be connected incorrectly by mistake.
The main air receiver line was finally included in the RIC regulations in 1975, so that since then it has been part of the basic equipment in international passenger coaches. For example, for this reason the SBB had to replace the coupling heads they had been using for around 50 years because they did not meet the now generally applicable standard (the color code was changed from green to white). The arrangement deviating from the RIC rule with internal connections of the main air reservoir line has not been changed for locomotives and passenger coaches that are only used in domestic traffic.
See also
- Main air line (HLL)
Individual evidence
- ↑ Swiss Driving Regulations (FDV) A2016 Federal Office of Transport (FOT), July 1, 2016 (PDF; 3 MB). R 300.14 Appendix 1, section 5.1.2 feed line
- ↑ Railway amateur 5/1975, page 224