Can someone explain what approach control is please as don't really know what it is. Something related to routing?
Courtesy of AI. " Approach control in railway signaling is a method that informs drivers of an upcoming route change by keeping a signal at danger until the approach track circuit has been occupied for a set amount of time. Approach control can be used in conjunction with other signaling methods to provide drivers with as much information as possible. For example, some systems use theater displays to indicate the approach speed. Others use route indications at major stations to direct arriving trains to the correct platform. Approach control can also be used to enforce speed reductions for diverging routes. For example, "approach release from red" keeps the junction signal at danger until the train is close to it. This forces the driver to apply the brakes and stop at the junction signal. Approach locking is another railway signaling method that prevents a route change if a signal has displayed a proceed aspect."
Basically yeah. As you approach the jcn the signal will display a stop aspect until it detects the train is moving at the correct speed. I think they are mainly used on mainlines, where the line speed is much higher than the restriction crossing over the jcn.
A good example of it in TSW is on the Midland Mainline DLC, If you're traveling from Derby to Nottingham you'll get warning signals on the approach to Long Eaton followed by a red protecting the junction, as you approach at a low speed the road will set giving you the turn off towards Nottingham.
I don't have that route but from my time on ecml it shows up a lot I feel. Can approach control be possible without a red signal (flashing yellows etc instead?) Also, how does it know when to release you from the red signal if it is red?
In a word yes it can, the signal can remain at red until clearing to a yellow, a sub or a divergent route to ensure that the approaching train is under control/travelling at the required speed for the junction or the possible restricted overlap. The timing is done off the track circuits, for example if track circuit one leading up to the signal in question is occupied for 30 seconds and the signal hasn't been passed at danger then the relays can work out that the train is at or under the required speed and clear the signal as the length of the track circuit is a known so the time required can be calculated.
Ah so it can be different signals etc for different speeds. IE one train could be still too fast and has to change aspect to allow train to slow in time etc
If you ever run a service from Preston to Blackpool North on the Blackpool Branches DLC, the signal just before Kirkham & Wesham station uses approach control. It is always set to red aspect, forcing trains to slow down below 30mph for the upcoming junction. Can't remember the signal number off the top of my head though, even after passing it a million times.
I don't know if it's UK-specific (I suspect not) but it's precisely what speed signalling at junctions is designed to replace.
It's a good system. There's been a few incidents recently where trains have passed over junctions (not protected by approach control) way too fast. And caused passenger injuries and even derailment! In most cases a train is travelling at speed passing green aspects when out of nowhere a junction signal comes into view, displaying a feather for crossing over! There's absolutely nothing the driver can do to slow the train down in time at this point. With approach control the signal will display a stop aspect, making both the approaching signals display yellow aspects giving the driver time to prepare to stop up ahead. By the time the train reaches the junction its crawling to a stop and will pass over the junction safely. If the signal clears of course. You shouldn't expect it to clear.
On a slightly related topic I'm struggling with the in-cab signals on US routes like Trenton or Boston when approaching a red signal at the end of a platform. I always get a penalty application and can't get to my stopping point. How do I get around this the "proper" way without just turning off safety systems for the last 100 yards?
It could be like uk signals where there's some kind of approach control. If you approach the signal too fast you will receive an emergency brake application. I don't know much about us signals. I believe cActUsjUiCe is the US signal guru.
Absolutely, and most of these signals are fitted with TPWS now as well (in track circuited areas) which provides a more accurate calculation of the trains speed and will initiate a brake demand if the train is travelling too fast for the junction. You also have fixed overspeed sensors in various places that also do the same thing in various places to stop drivers approaching terminal stations too fast etc and these in some cases will operate a group replacement setting to put all signals back to danger in an area to protect trains from a SPAD.
I always make sure I am doing no more than 20 before a red signal especially at termini stations on a route say at Doncaster on ecml or Peterborough so I am not caught out. I think that's the ideal speed?
That's what I figured but I'm already crawling along at less than 20mph enforced by the Restricted Speed aspect. It's happened to me coming into Trenton and Rahway because the stopping point is so close to the red signal.
The one important thing to remember about approach control, as opposed to being brought down by flashing aspects, is never assume the red will step up. Down that road lies the Cat A SPAD and slightly more than tea and biscuits with your manager!
Back in the day when I was an ATW Duty Control Manager and had our safety briefings from the chief Driver Manager including dealing with SPAD's, it was hammered home many times that, "But, but it normally steps up to green", was no mitigation and might even be a factor in whether the driver got relieved there and then or was allowed to move the train so it was clear of the main line first.
Sometimes you can get away with stopping short of the stopping point. I would try that or reducing the speed further.
If that works you for in game, go for it. A lot of TOCs employ a defensive driving policy now where they often creep up to signals at that speed or less, in some cases stopping a good 100m plus from the signal, and it sounds like your simulator experience reflects that. I can think of one terminal station where the overspeed magnet is set to 88.3mph around a mile from the station in a 50mph line speed, hitting it at the trigger speed would be exciting.
Are these tpws loops only just before the red signals or before. Where does it measure the distance? Can you get a brake demand at double yellow signals etc if going to fast And do the speeds that tpws triggers a brake demand depend on how loops are programmed or something else? As heard at Euston it's 15 mph over them to not trip but others have less and others more. As I see them over points etc so was just wondering how it all works. All I know is you have to not exceed 1 second passing over if I am correct. As it times it? Additionally, what is the general rule of thumb when passing over these.
I'm sure I either read on here or saw on a youtube video the drivers use a 15/20 rule - 15mph over the magnet and stop 20 yards from the signal. Not sure who the TOC was though
Yeah I do wonder if they get notice of what the speeds for issuing a demand is on a loop or just use rule of thumb.
Ok, that's some simple questions with some very complicated answers! As a rule of thumb TPWS and TPWS overspeed loops are only fitted where there is infrastructure that needs protecting, so terminal stations, junctions with potential conflicting movements etc. So you shouldn't get a TPWS warning for a double yellow, only an AWS alarm if fitted, however you may get a TPWS demand at a yellow if going too fast. Generally speaking you'll have 2 mat systems on your TPWS signal, one will be the overspeed protection well ahead of the signal and that will be the one that checks your speed and the 2nd will be at the signal itself as the SPAD protection (I think, its a long time since I trained TPWS). The signallers have a list of the trip speeds for the overspeed sensors for issuing speeding tickets as needed, but they don't have the trigger speeds for each individual signal as that's going to depend on linespeed, sighting, infrastructure, gradients and any other local factors that need to be taken into account. Drivers don't know the trip speeds of each signal, the biggest part of their job is judging speeds and stopping distances so they'll be well used to handling the trains, especially with the 15/20 rule mentioned above, which is a very good example of a TOC defensive driving policy.
The NYC Subway uses timer signals in certain spots, but that's the only US example I can think of. https://www.nycsubway.org/wiki/Subway_Signals:_Time_Signals
This happens to me as well, both on US / NEC routes and most recently on the WCML. I couldn’t finish my LO run at Euston because approach control (I’m assuming) stopped and disabled (permanently applied emergency brakes) my train before I could reach the platform marker. I’ve found CTRL+ENTER to deactivate safety works, but would appreciate it if they could figure out how to fix this, as I enjoy playing with safety systems on, and also enjoy running and finding runs on these routes without frustrating bugs popping up.
That's not approach control that's TPWS, when you go over the grid plates doing too high of a speed, for example on Euston platforms when approaching the buffer stops before you go over the last visible grid try to ensure your speed is less than 10mph irrelevant of what the track speed is saying.
Trent Junction is, or was, a bit of an anomaly. If you're approaching from Loughborough on the mainline, both routes to Nottingham and Derby are high permissible speeds, so neither required any form of approach control. The downside to this was that as you burst out of the tunnels at Ratcliffe and cross the Trent, and observe you've been routed for Nottingham instead of Derby, you have no recourse available as you aren't going to stop in time and are going to take the wrong route. I'd like to think that in the 15 or so years since I've been that way and they've resignalled the route that they've now used preliminary route indicators to show the status of the junction with enough notice to now query and get the route changed.
That’s a solid tip - thank you! Is there a way to recover the train and continue to the end of the platform after the brakes have been applied? I’ve tried a full shutdown and restart, and it still holds me with applied brakes.
Problem is if you're that close to the stopping point the game will just assume you stopped intentionally and you'll lose points for stop accuracy, but other than that there's no penalty or negative outcome of an EBA so close to the end point. To get out of a TPWS EBA I believe it's brakes to 1,2 or 3 - reverser in neutral and then press the TPWS reset button, then wait for brake pressure to recharge and then reverser to forward and apply power.
I don't see the issue with it.. You see a signal at caution you react accordingly, you then see the following signal at danger again you react accordingly, the danger then changes to a proceed and you apply power and continue on your merry way. If you have to come to a complete stop before approach control changes to proceed with caution then you need to address your driving style not blame the signaling system.
Agreed, it's no different than riding out yellows at a slower speed and pushing up against a red signal to change without stopping. It's not how fast you drive, it's how well you drive fast.
Never go so fast that you cannot stop, never go so slow that the dispatcher is getting ready to tear you a new one.
If I'm coming up to a red I'll make sure I cross over the AWS at 15mph. Then slow to a 10mph soon after and the expect to stop
Oh no, when I say I hate it, I mean when I’m driving certain types of trains, (Freight with 66’s for example) as a safety feature it is definitely a good idea to prevent over-speeding, but it can be a pain when you’re driving something that isn’t a 465 or 323. You have to brake, which itself can be tricky when you have no idea what the set trigger speed is on the approach TPWS grids, and you basically stop sometimes (or at least I do) and then you have to wait for 4 days for the brakes to release. That being said, it does make drives more fun, out of all the things on the UK rail network that are annoying, (to me that is) Approach Control and TPWS loops are definitely not fun, especially when you are new to a route and have no idea of the locations or on a incline in a heavy train. I still treat all red/yellow signals by slowing down, keeping in mind the location of the next signal and slowing down as I approach, after all there is not indication that differentiates stop from approach control. I have actually seen this in action in real life, it is used on the Tyne and Wear Metro in the tunnel from Monument to St James. The platform starter at Platform 4 is held a danger, when a train approaches it, it changes to caution. Then the intermediate signal (located between Monument Platform 4’s starter and the signal protecting the diamond crossover at St James) similarly follows when a train approaches, followed by the junction signal which changes when a train draws up to it, (fitted with a stencil theatre style route indicator, displaying either 1 or 2 for those interested) unless a train is departing platform 2. I occasionally travel this way so I get a seat, (you can sit at the front of the Metrocars) as Monument is often crowded and it is better than standing on a crowded platform. Although I believe this may be Moorgate Control. Here’s a video showing it
Going back to my ATW Controls and the Driver Manager briefings, the view was you put approach control out of your head. As a driver it doesn't exist, if you're checked down to a red you expect to stop. Any other mindset is a recipe for gross error.
Just to reassure you (and anyone else thinking of travelling by train in the near future!) this isn’t correct. You can’t get a route indicator (‘feather’) with a green signal for a diverging route with a significant reduction in speed without some form of approach control. There have been two serious incidents in the UK in the last few years involving trains going too fast over diverging routes. In both cases approach control was in operation, and functioned correctly. The problem was that once the train had slowed and the signal cleared, the Driver mis-read the signal as indicating that the train was to take the main route, and therefore took full power. The distance to the actual junction was sufficient that the train was able to accelerate to a speed well in excess of the speed for the diverging route by the time it reached the junction. The train therefore passed through the points at too high a speed. This highlights a risk with approach control signalling which has increased recently. Modern trains accelerate much more quickly, so if the Driver misreads the signal as indicating the train is to take the main route, there is a higher risk of it taking the diverging route at excessive speed than used to be the case. This risk has been highlighted in Driver briefings across the UK. This video explains the sequence of events in one of these incidents:
You're probably doing it wrong then. You shouldn't need to stop at an approach control signal unless there is danger ahead of the signal. This reads like you're braking too late and too harsh. IRL it's time based I believe (train is in track circuit for x time), so approach the red slow but not too slow you roll to a stop, and if you need to stop, stop on a light brake application, enough to prevent the train rolling back (this goes for reds in general tbh). As a general rule, go over TPWS OSS grids no faster than 20 approaching a danger signal, or no faster than 10 approaching a buffer stop.
As a driver as Oldvern alluded to we just treat it as a red and be prepared to stop like any other signal. Obviously with route knowledge you're aware of signals that are approach controlled but you should NEVER assume it will step up as its happened loads of times and people have been caught out.
The idea of approach control is one of the older rules these days, going back to the days of semaphore signals and stepping down; only clearing a stop signal if the signal in advance will also be showing a proceed aspect, so you would bring a train to a stand, or almost to a stand before clearing the signal. Something which TSW has never done interestingly enough, but I can see that it would be frustrating for players and a pain to implement.
I've always been wondering why the UK signaling system does not feature a "two-signals" junction approach like in Germany or France. In these two countries, if you are directed towards a diverging route with a reduced speed you are warned by signals that sometimes give you more than one entire block to slow down. For example, in Germany you can be shown Hp1 (green) + Vr2 (green+yellow) on the same signal, so you know that the block ahead is clear but you have to slow down to 40 km/h (if no other speed indication) before entering next block with Hp2, only because of an incoming diverging route. In France you can be shown "Ralentissement 30", (slow down to 30 km/h, which are two horizontal yellow lights) and when entering the next block, a "Rappel de ralentissement 30" (remind to slow down to 30 km/h, which are two vertical yellow lights) some distance before the junction (the speed limit actually begining at the points). You can also be shown a "TIV mobile à distance" (mobile distant reduced speed board, shown to the driver only if the path is set to diverging track) followed by a "TIV mobile de rappel" (mobile reminder speed board) placed some distance before the points.
Ok, will keep this in mind, I’ll admit, I’m not the best at driving Locos, but I definitely started to brake much sooner and not as hard than when I first started NTP.
