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Chasing signals
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furnessvale
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Years ago a secondman friend of mine told me how his driver was chasing signals with the unfitted Southminster to Mile End sand train, having topped the bank at Brentwood a little too fast to keep control.
Seeing the approaching signals gradually changing from a string of double yellows, to single yellows and finally reds, he was mightily relieved when the offending all stations passenger in front was turned onto the fast lines for a quick run to Liverpool Street.
The freight was "just" back under control as it entered the sidings at Mile End.
Seeing the approaching signals gradually changing from a string of double yellows, to single yellows and finally reds, he was mightily relieved when the offending all stations passenger in front was turned onto the fast lines for a quick run to Liverpool Street.
The freight was "just" back under control as it entered the sidings at Mile End.
Chasing signals is something you don't want to do. If you know you are following something slower just ease off the power and sit behind it on greens. If you know the road, and what you are following you should be able to do this without too many problems. Once you start passing double yellows you can't assume anything is going to step up. I mean you can't assume anything anyway, but don't be a slave to your diagram and drive defensively.
Surreytraveller
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Not everyone on here is a trainee driver with an instructor to ask
They weren't asking as an enthusiast. They clearly stated they were a Trainee. The best advice I can give for a Trainee, is to ask their Instructor. Do you suggest that they get driving advice from a forum ?
berwicksfinest
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Chasing signals, basically your following a train in front, whereby your running under cautionary aspects up to reds expecting them to clear as the train in front clears the section in front.
Never a very good idea as the wonders that are the Power boxes might keep a signal at danger for any number of reasons. but as your expecting them to clear. significantly increases the chance of a SPAD or at the very least a clean pair of undies
Hope that helps
Never a very good idea as the wonders that are the Power boxes might keep a signal at danger for any number of reasons. but as your expecting them to clear. significantly increases the chance of a SPAD or at the very least a clean pair of undies
Hope that helps
tsr
Established Member
Unfortunately this only works on big mainlines. In some urban areas the signals will rarely, if ever, show green during the peaks due to the frequency of services. This does add a great deal of risk, but the drivers simply have to be more vigilant to restrictive aspects and constantly monitoring signals and speed (and yes, many of them do find this very draining).
It is more of an urban driving technique as that's where you tend to get the most restrictive aspects. When out on the mainline with higher speeds and huge signal sections you tend to run on green or are able to run past a single yellow at 60mph
It's that risk which we are trying to eliminate. It's a good defensive driving technique and you tend to know when to use it and when to close up. The skill is to make that decision when to use a defensive technique and where you need to accept the risk and deal with it.
Which is why there are so many incidents. It isn't a case of being more vigilant. If anything, that tends to work against you because of the increased workload. Yes you are more aware and you increase your non technical skills but you balance that by using this kind of driving technique.
I though on a line with tr
I am thinking of somewhere like the fast lines out of Euston when there was a mix of 100/110 mph loco hauled trains and 90moh EMU's (312's?) with EPB brakes. The EMUS could stop from a yellow, while the loco hauled trains would need to start braking at a double yellow. This caused a problem with AWS in that the EMU driver would be constantly cancelling AWS warnings and may inadvertently miss the single yellow.
I thought on a line with trains of different top speeds and braking curves, some of the drivers would ignore the double yellows, treating them as greens.
I am thinking of somewhere like the fast lines out of Euston when there was a mix of 100/110 mph loco hauled trains and 90moh EMU's (312's?) with EPB brakes. The EMUS could stop from a yellow, while the loco hauled trains would need to start braking at a double yellow. This caused a problem with AWS in that the EMU driver would be constantly cancelling AWS warnings and may inadvertently miss the single yellow.
bramling
Veteran Member
You’ve sort of answered your own question, as “ignoring” a double yellow leads to the risk of missing the relevance of a single yellow should one crop up, with no distinct AWS to make it stand out. I’d imagine this is even worse on those few parts where there can be more than one double yellow aspect applicable to a given red aspect - as on the Electric lines into Liverpool Street (anywhere else?).
This is why multi-aspect signalling isn’t wonderful for dense suburban applications, as signal spacing and headways cause undesirable features to arise. LU (apart from the north end of the Met Line) does things differently, with repeaters only provided where sighting requires them, which means drivers generally run on greens, however this becomes less feasible as speed increases. Whilst two LU lines do have a mix, I don’t think it’s really good practice to mix the two setups, as it introduces risks. On LU that risk is generally mitigated by full-speed overlaps and trainstops.
but TfL operate trains with similar braking, acceleration and max speed. very different from national rail.
Harbornite
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Indeed.
bramling
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That’s what I mean, whilst the LU setup works for metro-type operations, it doesn’t work so well on a more mixed application. However, the more densely worked sections of NR do err more towards the LU attributes, which makes NR signalling less ideal, but as with all things in engineering it’s all about establishing a compromise.
Notice how the tunnel sections of Merseyrail have a slightly different signalling design, complete with trainstops.
Johncleesefan
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Route knowledge dictates that you can keep a good distance back so as not to be “chasing” signals on any route really. We have many 2 aspect areas and you know when the slow quarry train is in front and to generally reduce speed by 20 mph so as to keep a good distance back. It can be a tricky one to judge and certainly not one that can be taught easily. It’s cones from experience
Wilts Wanderer
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This reminded me of something I read about the slow lines out of Liverpool Street. The signal spacing is exceptionally tight in places, shorter than the maximum train length. The AWS magnets are sited pretty much immediate beyond the previous signal (which indicates about 200m between signals.) Yet the linespeed is as high as 50-60mph - this is possible because the normal 4-aspect signalling sequence (G-YY-Y-R) is augmented with extra YY and Y aspects. So it is actually G-YY-YY-Y-Y-R. Whilst this reduces the number of single yellows encountered by the stopping trains which are formed by 700 units which can stop on a sixpence (as could the 315s before them), it makes it rather hairy for drivers of freights and diverted IC trains at weekends if the fast lines are shut, consequently these trains tend to run very cautiously and cause delay.
If you don’t believe me, watch this video which shows just how close the signals are spaced, partlcularly in the Bow Jcn-Stratford-Maryland area.
as a experienced driver you will never ever chase any thing as that suggests you are approaching out off control to some extent
you will off course proceed in a safe often single yellow /red fashion
most train driving is fully automatic with the out off routine requiring perhaps 15- 20% off your attention
cautions and reds should be very relaxed as they are often a frequent day to day situation but most off your brain power should be there for the odd break down on unfortunate situation
you will off course proceed in a safe often single yellow /red fashion
most train driving is fully automatic with the out off routine requiring perhaps 15- 20% off your attention
cautions and reds should be very relaxed as they are often a frequent day to day situation but most off your brain power should be there for the odd break down on unfortunate situation
Reminds me of when I commuted on the GEML, sitting at the front of the train and hearing the buzzer going for every signal, and very rarely the bell for a green.
furnessvale
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I wonder if the definition of "chasing signals" in this thread is somewhat blurred?
I take it to mean that restrictive aspects in front are continually clearing when approached, NOT that there is a conscious effort to catch up to those signals and force an otherwise unnecessary brake application.
Note that my example at #4 was not such a conscious effort as it was an unfitted freight out of control until the gradient eased.
Mordac
Established Member
Since we're on this subject, can drivers here give their opinion on what the introduction of C-DAS will mean for your practice in these cases. This is an enhancement to the Driving Advisory System (? not sure I got the A right) whereby it's actually connected to the signalling centre, and so can advise drivers that, e.g., they're following a freight, so should reduce speed to match it, or that there's delayed trains at junctions further ahead, etc.
I haven't used it yet but speaking to other Drivers I don't hear many positives.
For me personally I believe that every little helps and it it adds to my job or helps reduce my workload in some way then I'd happily support it. Driver aids must support the Driver and work in an intuitive and helpful way. I'd also say that it shouldn't be mandated and allow for flexibility in performing the job rather than becoming another restriction.
Mordac
Established Member
I don't think C-DAS, (as opposed to the plain unconnected version which just works off the working timetable) has actually been introduced anywhere in the UK mainline, has it? I think Chiltern were looking at being the first ones to do it, but this might be out of date by now, or I might be misremembering entirely.
DanDaDriver
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This is one of the times where the job really is as easy or difficult as you want to make it.
You can ease off and roll about catching the greens at a nice steady speed, easily able to stop if you start slipping.
Or, you can dash about, cancelling magnets and running upto reds, massively increasing your risk, maybe clawing back a few seconds which no one will thank you for.
When you’re on restrictive aspects get the brake in, you’re on the signallers time from that moment, not yours.
I remember the old grizzled “worked my way up from BR traction Trainee to second man to relief Driver in the good old days,” instructor used to keep telling me:
“F*@!k ‘em, if they want you to go fast they can give you green signals.”
You can ease off and roll about catching the greens at a nice steady speed, easily able to stop if you start slipping.
Or, you can dash about, cancelling magnets and running upto reds, massively increasing your risk, maybe clawing back a few seconds which no one will thank you for.
When you’re on restrictive aspects get the brake in, you’re on the signallers time from that moment, not yours.
I remember the old grizzled “worked my way up from BR traction Trainee to second man to relief Driver in the good old days,” instructor used to keep telling me:
“F*@!k ‘em, if they want you to go fast they can give you green signals.”
Deepgreen
Established Member
You'd support it if it "adds to your job" or "helps reduce my workload" (my bolds) - mutually-exclusive, surely?
Deepgreen
Established Member
The helpful response would have been to state the meaning and suggest confirming with trainer, etc. That way, everyone may learn and the spirit of the forum is upheld.
There are no holes in this argument, it's just flaking paint.
Let's put this to bed shall we.
I answered the question, in full, with a specific example and giving good description of how and why it happens as well as posting the advice for the Trainee. (feel free to confirm that with the OP)
The OP responded with a thanks, that's why it's there.
Then the forum formatting swallowed the post (posting on a phone is a total drama lama)
Then bionic replied with another explanation.
Then, because the information was already out there and the discussion was/is continuing. I don't see the point in reposting the same information for the umpteenth time.
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