Function Punktförmige Zugbeeinflussung

1 function

1.1 1000-hz speed limiter
1.2 500-hz speed limiter
1.3 2000-hz emergency stop
1.4 operation

function

pzb inductor ( trackside antenna )



pzb onboard transmitter mounted on tram

locomotives , multiple unit cars operating cabs equipped onboard transmitter coils superimposed frequencies 500 hz, 1000 hz , 2000 hz. passive tuned inductors (rlc circuits) situated @ appropriate trackside locations; each inductor resonates @ 1 of 3 frequencies, depending on location. when leading end of train passes on 1 of trackside inductors, inductor s presence detected onboard equipment through change in magnetic flux. activates appropriate onboard circuit , triggers whatever action required based on location (e.g., audible/visual warning, enforced speed limit, or enforced stop).

the 3 frequencies have different meanings train:

1000-hz speed limiter

warning distant signal being passed shows caution , drop of speed required. driver has confirm has seen caution aspect pressing button; failure within few seconds results in forced stop.

the 1000 hz active along yellow signal on distant signal before main signal, or on main signal combined distant option following main signal, or active before railroad crossing.

the train driver has acknowledge cab signaling within 4 seconds (2.5 seconds on trains mvb electronic bus) hitting button - called vigilance test (german wachsamkeitskontrolle ). failing result in emergency stop.

after acknowledging warning signal train has stay below braking curve (german bremskurve ) - fast trains may travel 165 km/h , must reduce speed below 85 km/h after 23 seconds. note operation of high speed trains beyond 165 km/h not based on visual wayside signals or pzb inductors (using lzb or european train control system cab-signalling instead in germany).

the train cannot released speed restrictions within 700 m after 1000 hz activation. after point train driver may hit release button (german freitaste ). in later generations enforced speed limit extended 1250 m , 700 m point relevant 500 hz inductor.

the monitored speed (german überwachte geschwindigkeit ) depends on train type in direct relation mass , braking capability - quotient of these given in braking percent (german bremshundertstel ). if train speed drops below switch speed (german umschaltgeschwindigkeit ) restricted mode activated - includes constant maximum speed of 45 km/h 500 hz inductor lowers speed further during restricted speed control (german restriktive geschwindigkeitsüberwachung ).

500-hz speed limiter

immediate maximum speed (vmax) further drop of speed enforced.

the 500 hz inductor can found shortly before main signal actives speed control next 250 m. extend braking curve vü1 1000 hz main signal. restricted mode after 1000 hz followed braking curve vü2 reduce speed main signal. while switch speed @ 10 km/h after 1000 hz speed limiter (reflecting full stop of train) follow braking curve being again no more 10 km/h @ position of main signal. actual braking curves depend again on train type (which based on braking percent train driver has calculated).

2000-hz emergency stop

pzb buttons - command ( befehl ), release ( frei ), vigilance ( wachsam )

stop. if train overruns stop signal hit 2000-hz inductor activates emergency stop (unless overridden, see below). based on overlap after stop signal train can safely halted. because of different mass , braking capability of each train can asserted based on given maximum speed must maintained @ point of red signal.

the original indusi protocol placing 2000 hz inductor @ every visual main signal show red signal immediate stop. if train driver overruns red signal emergency stop enforced unconditionally. 1000 hz inductor conditional restriction commonly placed @ every distant signal show yellow signal pointing following red signal - in original indusi protocol train driver has acknowledge bell ring within 4 seconds or train halted automatically. based on yellow signal train driver required lower speed allow overlap after stop signal enough halt train safely. indusi system speed limiter (at least since i60r) enforce maximum speed after given time in situation maximum speed depending on type of train. 500 hz commonly found near railway stations or shortly before main signal - activates lower speed limit 1000 hz inductor. since visual signals may switch off while train moving, i.e. no red signal anymore after crossing yellow signal, train driver can release train enforced speed restrictions using button allowing accelerate free section ahead.

operation

the details of operation have changed on time , later pzb systems allow more granular speed restrictions. basic part of operation scheme (german betriebsprogramm ) of pzb90 protocol still use 3 inductor types seen in following picture. diagram shows speed (german geschwindigkeit in km/h) in accordance braking distance (german bremsweg in meter) before , after main signal (placed @ 2000 hz point).

a train driver may pass across stop signal if has been mandated station director, or being allowed replacement signal (german ersatzsignal ) or caution signal (german vorsichtsignal ). train driver needs push , hold command button (german befehlstaste ) while moving on active 2000 hz inductor - while button pressed constant audible warning (bell , speech) raised , use of command button registered on train recorder. while using command button maximum speed of train limited 40 km/h.