I think only locomotives have receivers, not each car. On multiple units, there could be more than one, but I guess only the one at the leading end would be active, because German signals turn red immediately after the tip of the train passes them. Or do they work by detecting an interference? But I don't know how it'd work with radio waves, I don't think you can send targeted beams at such high wavelengths like that without too many false positives. Or, maybe a track circuit detects the train SPAD'ing on reverse and sends a signal to the 2000Hz to alert the locomotive receiver, but again, aren't these magnets supposed to be very very short range?
Safety systems are always active only on the leading cab of the leading engine, all others are either turned off, or set into a corresponding mode of non-leading vehicle where possible. In reality the signal change is not as instant, it takes few seconds, but for example pushing loco at the rear of the train (which can be even manned) would still always pass all signals on red, as front of the train passed them a while ago already. Additionally, PZB in particular is mounted only on one side of the tracks, so the rear cab of loco or unit has the receiver on the opposite side of the train completely and similarly the leading cab does not interact with signals for opposite direction in any way.
Exactly. A train won’t run backwards unless it’s shunting, in which case PZB is usually disabled anyways.
Overshooting a station, entering the wrong track(manual switches), also in the case of Boston Sprinter with ACS-64, just to maneuver into the station(and I'm pretty sure most single unit passenger trains without cab cars do it, though it's rare in Europe nowadays). If you try to reverse with the PZB on, weird things happen. I can't confirm that the 2000Hz gets activated, but 1000Hz starts flashing and you get forced braking, acknowledging or Befehl40 doesn't change anything. So if you overshot the station with an S-Bahn, you have to switch off the PZB to be able to reverse.
They physically can’t be since the track-side magnet and the one on your loco are on different sides. Yes, 1000Hz starts flashing and I believe you’re being monitored as not to exceed 100km/h. This is the normal ‘reversing’ monitoring. Obviously, it’s not that simple in real life, you can’t just reverse into a station because you overshot. However, there’s no need to turn PZB off, you can reverse no problem. Not how it’s done here. A shunter will push the coaches into the station with the loco being driven (solo) to the waiting coaches. The driver is always in a lead cab and doesn’t reverse into place. The point is, there is no problem reversing under PZB monitoring, but it’s nowhere near as common as you seem to think it is. It’s so rare (apart from switching, in which case PZB is deactivated most of the time) that no proper PZB supervision is needed.
If by here you mean Germany, almost every passenger train there either is a multiple unit or has a cab car so it's a moot point, they don't have fixed leading ends. But in Boston, the electric amtrak literally backs into the station(diesels have cab cars), it's in one of the scenarios. It's a pretty long ride too, on the ballon loop south to the station. I don't know how it's done in real life, maybe the conductor waits with a walkie talkie at the rearmost car and directs the driver, but it's a train driving in reverse nonetheless. Also a bit of reversing is unavoidable if the station has dead ends rather than continuous tracks(most large stations do). Even if there are switches to the other track where the locomotive can decouple and head to the other end of the train, which there aren't in this game other than West Somerset, if the locomotive has stopped after the switch, then it will need to reverse. Also there might be another train already on the next track rendering this impossible.
I know. However, Amtrak practices are irrelevant for PZB for very obvious reasons. Yes, which is why I said it’s nowhere near as common as you imply it is. OK, let’s get into bureaucracy. Any of those movements you describe are classified as ‘shunting moves’. What that means is that you’re not allowed to exceed 25km/h and must be prepared to stop on sight. As such, PZB literally wouldn’t do anything if you were under normal monitoring. 25km/h is lower than any monitoring it can enforce and the 2000Hz magnets are irrelevant: As a ‘shunting move’, you’ll only get shunting signals meaning that all of the 2000Hz magnets on your trip are active and need to be passed using the ‘Befehl 40’ button. Therefore, none of PZB’s functions apply to shunting, wich results in two things: 1. PZB is to be turned off when shunting for longer than 30 min (yes, that’s in the official rules). 2. There’s no need for monitoring reversing moves as all of them will be ‘shunting moves’ anyways. Hope that clears things up a bit.
That is exactly how it is done in the US. I have done it before on crew at a museum railroad and I’ve seen Amtrak do it as they back into the Tampa station. It requires constant communication. The conductor is riding the rear car and calling out all the switches, signals, and grade crossings. The conductor is also telling the engineer how many cars ahead the track is clear. Typically, if the line is clear, the conductor will say “Clear for six cars.” This is about 500 feet. If the train has traveled three cars after that point and the engineer has not heard further from the conductor, the instructions are to stop. It is called “ protecting the shove.”
Do you need to use PZB when you're driving a single locomotive on the mainline? Such as the Lübeck scenario where you go to tow a failed passenger train with a BR 182. Since single locomotives can stop on sight of a red signal at any track speed(160 kmh and below), PZB might not be necessary. But I think PZB is a pretty punitive system compared to PTC and ATC in the US, or TPWS in the UK. If you exceed speed limits in these systems they give audible warnings for you to slow down, and even if you get forced braking, you can release it after a certain amount of speed lost, unlike PZB which is always to zero kmh and is always activated the moment you go 0.1 kmh above the limit. Also it sounds a bit overly protective for S-Bahn which can decelerate from top speed to zero kmh at max braking in a single signal block without using emergency braking. Does the U-Bahn also use PZB? I don't think there is a U-Bahn DLC yet but I mean in real life.
I can’t speak for the US but the UK TPWS is pretty brutal when it wants to be. There are no signs or warnings, it will just slam on the brakes if you are 0.1 mph over the set speed approaching a restricted signal, speed restriction or buffer stop. The AWS is a lot simpler and is the one where you get the audible warning that you have to acknowledge. These two systems together make for a very safe system but they are not present at every signal or speed restriction in the UK unfortunately.
I don't know how overshooting a station works in Germany but here in the UK the train wouldn't reverse back to the station, it would carry on to the next station.
I may have confused it with another UK train control system which only applies the penalty brakes until the speed restriction plus some more, unlike PZB's absolute zero.
Most definitely, yes. PZB is mandatory even if you're just running a single loco. If PZB is turned off the maximum allowed speed is 50 km/h. U-Bahnen in Germany are regulated by a different set of operating laws. While regular railroad is covered by the EBO, the Eisenbahn-Bau- und Betriebsordnung, subways and trams are regulated by the BOStrab (Straßenbahn-Bau- und Betriebsordnung). Since BOStrab doesn't regulate safety systems as narrowly as EBO there's not really a common standard like PZB, LZB and ETCS. U-Bahnen usually use proprietary systems, although they tend to be closely related to PZB and LZB.
It’s not. A lot of stricter requirements (specifically in regards to the starting monitoring and 500Hz magnets) were implemented because of a terrible S-Bahn accident with a Br 420.
Could the BR 420 brake as effective as modern S-Bahn trains though? Also today, S-Bahn drivers can see the next signal on their Ebula displays. Also what kind of accident was it that the both 1000Hz and 2000Hz magnet couldn't stop the train? He must have been overspeeding crazy, because most junctions where two trains can actually meet head-to-head have speed limits of 60-80 kmh
That’s false. You can read up on the most impactful of several accidents here. A driver forgot the red signal in front of him while overseeing the boarding of the train. He accelerated out of the platform and the 2000Hz-induced penalty brake application was not strong enough to stop the train before pulling into another train’s path. Look, I appreciate curiosity and trying to learn, but why are you so hellbent on getting rid of PZB?
So he didn't even try to brake. I said that there could be another PZB mode for S-Bahn and other light rail, because when the 500Hz gets active you still have enough braking distance to go from 80 to 0, but the PZB insists you come in slow like a super heavy freight train at 44.9 km/h.(meaning 35 or less in reality) Luckily, timetable is set up in a way that you don't encounter many yellows and reds while driving on the S-Bahn. I wouldn't want to get rid of the PZB, but I don't think it'd become less safe if penalty brakes could be released if the speed restriction was met, like the ATC, and 1000Hz magnets gave audible and visual warnings to acknowledge them like the Sifa.
I don’t understand what you are saying, PZB is trying to stop you like a super heavy freight train?! A heavy fright train will have a completely different braking curve imposed by PZB, are you aware of this? It’s called PZB mode and it has three different settings. Passenger services will run in the upper mode, allowing much faster restriction speeds then the lower mode for „super heavy“ fright trains. And all these speeds come down to worst case calculations under certain conditions. If you don’t see the sense in some of those speeds, it would probably mean that you have not fully understood the system?! Did you know that after every PZB penalty braking in the real world, the driver has to get in contact with the signaller and discuss the reason for the braking. This is an additional safety measure, in case the driver has not fully understood why the system has stopped him. Many of the accidents happen, because the driver has misinterpreted the penalty braking, releases himself without the chit chat with the signaller and did not even realise that he has just passed a red signal (there are other Szenarios as well, obviously). This is why it always stops you completely! This is all there for a reason, this is how this system works, if you like it or not.
Yes, I already said there could be another PZB mode for S-Bahn. Don't know about real life but in the game on a completely level surface, BR 422 typically brakes with 1.6 m/s^2 deceleration, on max brake(not emergency). Using Newton's laws of motion, that only gives us 49 meters of stopping distance from 45 km/h(the 500 Hz limit for passenger trains in restricted mode), but the distance between the magnet and the red signal is 220 meters or more. If you wanted to stop at 200 meters using max brake(20 meters away from the red) after passing the 500Hz, then your max speed would need to be 91 km/h. I don't know how to be more clear to be honest. Another thing with PZB is even if the upcoming speed restriction is higher than 1000Hz restriction, you still have to slow down to 1000Hz speed then accelerate again. Pretty annoying on Mode U when you have to slow down to 55 kmh(which usually means 45-40 in actuality) because of a 80 kmh restriction and you lose all of your momentum and take ages to get back up to 80 kmh.
There actually are a few versions of PZB in regular use that do exactly that. One of them is PZB 90 AVG, named for the Albtal-Verkehrs-Gesellschaft, operator of the Karlsruhe Stadtbahn and pioneers of the Karlsruher Modell tram-train concept. They are quite local to me so it's a subject I'm quite familiar with. Since they run under both EBO and BOStrab conditions, sharing tracks with anything from trams to ICEs, they naturally have to adhere to both sets of regulations, which also includes the need to have very strong brakes to be allowed in inner-city traffic. And by strong I mean strong, as in stronger than pretty much any average modern EMU. With their light weight and track brake it's like throwing an anchor. You do not want to be standing when an AVG driver gets caught by a 500hz magnet. It's not exactly fun, even when you're seated. Speaking from experience there. Due to these fairly special circumstances their mode of PZB includes things like 1000hz restrictive mode being limited to 65 km/h instead of 45 km/h and, if a 500hz magnet then follows, it will be a regular 500hz Beeinflussung instead of switching into 500hz restrictive mode. PZB 90 AVG is also used by the RegioTram Kassel and the S-Bahn Hamburg also uses their own modified version of PZB.
Well, there you have it… the real deceleration of the BR422 is more like 0,9m/s2, not 1,6. Also, not every braking system may be used for calculating the max braking performance, the E brakes usually have to be ignored, as they would only work with electrical power, which may not be there in a real emergency. I do understand that it is annoying when you have to brake your heavy cargo train to 55km/h, even though the upcoming speed restriction is only 80. however, I would challenge you to think about the meaning of the „P“ in PZB;-) This is how the system works and is laid out for. Nothing you can do about it. I mean, I am annoyed as well, when I am driving my car through the city at 3am in the morning and I have to stop at a red light, even though I am the only one around. In the name of safety I still do it, though. Besides, there are methods to avoid you from PZB activation for a speed restriction below 90kmh. When your speed is checked (using a GPA) before you hit the 1000Hz magnet. On DRA you have this implemented as well in TSW, when you arrive below a certain speed the 1000Hz magnet is not activated and you don’t have to slow to 55 for your upcoming speed restriction.
Did some research for you based on Labra’s inputs. According to this discussion, you need BrH of 250 for special rules to be considered. That’s a value impossible to reach without very strong MG-brakes. In fact, I doubt anything but trams reach that. Also, as OpenMinded said, 1 m/s^2 is way more realistic (and what you find online for the 422) than 1.6m/s^2.
Maybe just to add to this. Certain railway operator, who operate outside of the normal DB infrastructure do have certain adaptations. S Bahn Hamburg is one of them. They are using PZB90s in mode M, but the braking curves are adapted and also some restrictive modes are disabled. You may find this interesting: https://fahrweg.dbnetze.com/resourc...etzzugangstests_pzb_90_sbahn_hamburg-data.pdf Also, if it is considered that the limitations of PZB are in the way of the required capacity you can always install a LZB system. This was done on the S Bahn Munich. But also tram operator in Germany are using LZB to increase capacity. Nowadays, though, this gets removed again and PZB is installed, as happened in Dusseldorf, recently… PZB is simply much much cheaper to operate.
You realise, that the 500Hz is to keep you away from speeding over a Signal after you stopped, as well as keeping you away from speeding over the signal on approach with 85. And 85 isn't that far of your 91. Both cases are covered, the only one that isn't, is the signal clearing after you passed the 500Hz.
I guess, but with the push for more automation in everything vehicular nowadays, sooner or later they'll have to install LZB or its modernized successors everywhere. Even if they don't get rid of the human driver for some time, they may want to delegate him to the role of a Sifa presser(and a backup driver in case of LZB failure). I'm not saying that's the correct way of approach to industrial design and human operators are inherently less safe, but that's the zeitgeist of this century. Also since people in Germany usually complain about DB trains being late, something like universal linear train control coverage would probably mitigate this issue a lot, especially if they got rid of physical signal blocks entirely and the signaling was just based on spacing and speed, with no fixed greens or reds etc. Sounds like it would make trains a lot more punctual, and it's definitely possible with today's technology but too expensive for anyone to consider it.
LZB will never be installed on new routes again, it’s a thing of the past, the Industrie is not actively supporting it any more. Besides, what you can do with LZB you can also do with ETCS, which is considered cheaper as well. Your idea with the linear train control, I have seen this to be referred to as the moving block. Apparently, it’s not a matter of money, but rather technology itself. Or better current regulations. With todays Technologe it is not considered to be achievable under current safety rules. But it certainly is something on the radar of the industry.
^^ LZB was introduced in the 1970's and is successively being replaced by the standardized European Train Control System ETCS.
