Speed limits and making up time

[Sunset route]

The converse of the latter is when signallers fail to clear routes promptly, as happened again this morning when the GWR Reading to Redhill 0830 arrival was held outside Redhill for several minutes before receiving the shunt aspect to enter platform 1, where the north end was occupied by a Southern unit (this is a regular move during the emergency Southern timetable). The previous movement at platform 1 had been more than ten minutes before (from RTT), so this must be assumed to have been inattention by the signaller. The connection to the Victoria train on the adjacent platform was missed as a result, with the GWR train arriving 5 late and departing 4 late. All knock-on effects from what appears to be slack operating (an all-too-common feature of Redhill).

Jus a couple of points, signallers is prohibited from platform sharing or bringing attaching train into a platform until it's is confirms there is enough room for the second train.

The other point is that the siganl coming into Redhill from Riegate has one of the harshes approach controls when the subsidiary siganl is being used, approx nearly minutes long once the berth track circuit has been occupied.

 

[matt_world2004]

I have a number of questions about speed limits,

1.) It is mentioned here that timetables are based on the line speed limits. so if the speed limit of a line is 70mph, that train would be timed for 70mph running in its timetable, wouldn't that mean that every train is late, because the reality is a driver is not going to be able to hit a perfect 70 all the time, or is it actually timed based on a 65mph running if the speed limit is 70 on the understanding that the driver is likely to hover around somewhere between 62 and 67 mph on a 70 mph line speed limit

2.) do they have seperate operational and line speed limits to prevent bunching when rolling stock of two different types share track: For example, when the relief lines on GWR are down for maintenance, the high speed lines are used by the networkers who have a lower speed limits than the Intercity 125, Isnt it better during this time to run the Intercity 125 at the networkers top speed , rather than the intercity's top speed, Even if the line can cope with the Intercity's top speed. Likewise wouldn't this mean that at different times of day the line speed changes depending on what rolling stock is using it?

 

[70014IronDuke]

Coasting has been commonplace for many years; advisory signs at appropriate places on the network have existed for quite some time - probably amongst the older lineside signage I see on a daily basis - and coasting has been long appreciated as a viable method of maintaining or reducing to an appropriate speed. ...

And saving energy.

I believe the Southern Railway (I mean, the 1921 one, not the current mob) tested for and introduced coasting boards before WW2, with appropriate instructions (and explanations) for 'motormen' in the cabs.

 

[Ianno87]

I have a number of questions about speed limits,

1.) It is mentioned here that timetables are based on the line speed limits. so if the speed limit of a line is 70mph, that train would be timed for 70mph running in its timetable, wouldn't that mean that every train is late, because the reality is a driver is not going to be able to hit a perfect 70 all the time, or is it actually timed based on a 65mph running if the speed limit is 70 on the understanding that the driver is likely to hover around somewhere between 62 and 67 mph on a 70 mph line speed limit

2.) do they have seperate operational and line speed limits to prevent bunching when rolling stock of two different types share track: For example, when the relief lines on GWR are down for maintenance, the high speed lines are used by the networkers who have a lower speed limits than the Intercity 125, Isnt it better during this time to run the Intercity 125 at the networkers top speed , rather than the intercity's top speed, Even if the line can cope with the Intercity's top speed. Likewise wouldn't this mean that at different times of day the line speed changes depending on what rolling stock is using it?

1) Running times are usually calculated with the traction running at (say) 95% of their theoretical capability, giving some allowance for defensive driver behaviour, and traction having less and less "oomph" over time as it ages. Running times will then be reviewed and updated periodically based on actual operation experience (I.e. Stopwatch timings and observed data), which should reflect what drivers actually do in practice. Some areas also build a standard 5% 'recovery' into running times.

2) Generally no, the timetable will factor in differing performance characteristics and space trains accordingly. For example, at Euston, the xx.13 London Midland departure is timed at 100mph most of the day, running on the Fast Lines to Ledburn Jn (Leighton Buzzard). The next Pendolino (125mph) departs Euston at xx.20, but catches up to be minimum headway behind (3 minutes) upon reaching Ledburn Jn. During hours of two track operation, the fastest trains are artificially 'slowed down' in the timetable through addition of pathing time (I.e.planned extension to individual point-to-point running times), where they would catch up with a stopping train in front.

On the GWML Main Lines, HSTs and Turbos balance each other fairly neatly on a run from Paddington to Reading, calling at Slough. What a Turbo lacks in top speed it makes up for in superior acceleration, plus a shorter dwell time at Slough (with power doors), so the overall Paddington to Reading running time isn't hugely different between the two.

Also note that the Oxford departures are generally (I think) xx.21/51. These are followed by the xx.25/55 Heathrow Express services, and only then by the following xx.30/00 HSTs non-stop to Reading. So the xx.21/51 can run slower and stop at Slough and drop into the gap left in the timetable by the Heathrow service, which diverges before Slough. Another example of how timetable structure is optimised to account for different running speeds.

 

[The Planner]

1) Running times are usually calculated with the traction running at (say) 95% of their theoretical capability, giving some allowance for defensive driver behaviour, and traction having less and less "oomph" over time as it ages. Running times will then be reviewed and updated periodically based on actual operation experience (I.e. Stopwatch timings and observed data), which should reflect what drivers actually do in practice. Some areas also build a standard 5% 'recovery' into running times.

That depends on what system is used to calculate them and even then that only really applies to acceleration and braking for start to pass, pass to stop and start to stop SRTs. If a section has no other factors then its timed as line speed over the distance. 95% of max traction is used in systems such as Railsys with other factors for acceleration and braking (I think DMUs are still calculated as 0.78 m/s² to a point of 0.588 m/s² where it is considered constant). The 5% is used on the Southern as they have no engineering allowance, that is factored in to every SRT. As for reviewed periodically

2) Generally no, the timetable will factor in differing performance characteristics and space trains accordingly. For example, at Euston, the xx.13 London Midland departure is timed at 100mph most of the day, running on the Fast Lines to Ledburn Jn (Leighton Buzzard). The next Pendolino (125mph) departs Euston at xx.20, but catches up to be minimum headway behind (3 minutes) upon reaching Ledburn Jn. During hours of two track operation, the fastest trains are artificially 'slowed down' in the timetable through addition of pathing time (I.e.planned extension to individual point-to-point running times), where they would catch up with a stopping train in front.

Pathing time should only be added to keep the trains apart to the headway value as you state, not to inflate SRTs on their own. Two track timetables are calculated on the slow line speeds regardless of which lines are blocked with additional engineering allowances to factor for TSRs.

 

[Scott M]

If trains are timetabled to be running at 95% of line speed, that doesn't leave much leeway for coasting, defensive driving and driving slightly below the limit so as to avoid accidentally exceeding it?

Do most new drivers struggle to keep to time? And how strict are TOCs when it comes to keeping to time?

Thanks for all the responses btw, my initial questions have been answered.

 

[najaB]

...that doesn't leave much leeway for coasting...

Trains can coast for a surprisingly long distance on the level without losing much speed. To whit:
[youtube]6K3MQ_hn6XY[/youtube]

 

[The Planner]

No, not 95% of linespeed, 95% of the capability of the traction type.

 

[Scott M]

Trains can coast for a surprisingly long distance on the level without losing much speed. To whit:
[youtube]6K3MQ_hn6XY[/youtube]

Seen that video but aren't some coasting boards placed before a train would have reached line speed?

No, not 95% of linespeed, 95% of the capability of the traction type.

Ah fair, still doesn't give much leeway for defensive driving etc though!

 

[ComUtoR]

No, not 95% of linespeed, 95% of the capability of the traction type.

Apologies for my impending stupidity but... Does that mean it is timed for 95% of the Max Traction speed ? eg a 100mph unit that uses that part of the line ?

What do you mean by Max capability ?

Cheers in advance.

 

[The Planner]

As in the acceleration capability and overall power of the traction. If you had a power handle that went up to 100, if you had it in 100 we assume its only 95.

 

[ComUtoR]

Cheers for the reply.

I run 75mph traction on 100mph line and 100mph traction on 110mph line. Both have traction that is capable of linespeed. Does that mean that it isn't possible to keep to the timings ?

Ta again.

 

[The Planner]

It will be timed at the maximum speed it can achieve between two timing points, so a 75mph unit is timed at 75mph and 100mph unit at 100mph if its capable of doing it.

 

[ComUtoR]

DOH ! Of course.

So as long as linespeed is under the max traction speed then it should keep to time. Is it safe to assume that when the linespeed exceeds the max traction then it also doesn't matter as each unit has its own timings/diagram so a 75mph unit on 100mph line will be timed at X and a 100mph unit will be timed at Y

Does it matter which line/path your timed to ? If I'm pathed over the slow with a max linespeed of say 60 but the fast had a linespeed of 90 would there be different timings based on booked pathway or is it averaged out in some way between stations. I'm talking diagram wise as I could understand that each line of route has its own section times.

Cheers Mr P Your star of the day

 

[Bald Rick]

DOH ! Of course.

So as long as linespeed is under the max traction speed then it should keep to time. Is it safe to assume that when the linespeed exceeds the max traction then it also doesn't matter as each unit has its own timings/diagram so a 75mph unit on 100mph line will be timed at X and a 100mph unit will be timed at Y

Does it matter which line/path your timed to ? If I'm pathed over the slow with a max linespeed of say 60 but the fast had a linespeed of 90 would there be different timings based on booked pathway or is it averaged out in some way between stations. I'm talking diagram wise as I could understand that each line of route has its own section times.

Cheers Mr P Your star of the day

Timings are per individual line. Up lines, down lines, fasts, slows (reliefs for those watching in the itv West Country region) can all have different sectional running times between timing point A and timing point B. Which ever individual line the train is diagram end to follow, that is what it will be timed for.

 

[najaB]

Timings are per individual line. Up lines, down lines, fasts, slows (reliefs for those watching in the itv West Country region) can all have different sectional running times between timing point A and timing point B. Which ever individual line the train is diagram end to follow, that is what it will be timed for.

And also by traction type. And based on stopping v passing.

Sent from my Nexus 4 using Tapatalk

 

[redbutton]

I know it's a bit late, but to address Deepgreen's comments about the Redhill area:

It's easy to miss the subsidiary signal if you're not looking directly at it. If, for example, you're checking your diagram or taking a drink of water/tea/etc then until you look back up at the signal you may not notice the two little white lights next to the big bright red. Red changing to yellow or green is a lot easier to spot in your peripheral vision. Also, if the driver isn't expecting to enter an occupied platform (it doesn't show on the diagram unless you're due to attach), he or she may be calling the signaller to confirm the available platform length. Then there's the whole getting-the-train-moving procedure which can take a good 10-15 seconds.

On that last note, Electrostar units don't like to switch directly from regenerative braking to taking power. If you're below about 10mph when the signal clears, it's best to just stop and restart. This also allows time for the driver to check that his or her signal has actually cleared and he or she isn't actually reading across to a signal for another line. Also, if I know I'm not yet clear into the station (taking into account how many signals are between here and there), then I might hang back a bit so that the next signal might clear before I get there.

And with regard to the broader discussion about speeding to make up time: I, like most drivers I know, don't give a rodent's posterior about what time it is when we're in motion. I check the time if I'm stopped at a red (to fill in the report later) and if I'm stopped at a station (to make sure I don't leave early since I'm usually DOO.)

When driving between stations I'll always go as fast as I'm comfortable taking into account signal aspects, any applicable speed restrictions, route features (gradients etc), and traction conditions (some units brake better than others). I'd much rather reach stations early and have to wait there than try to time it perfectly and have to rush through station duties.

 

[Deepgreen]

I know it's a bit late, but to address Deepgreen's comments about the Redhill area:

It's easy to miss the subsidiary signal if you're not looking directly at it. If, for example, you're checking your diagram or taking a drink of water/tea/etc then until you look back up at the signal you may not notice the two little white lights next to the big bright red. Red changing to yellow or green is a lot easier to spot in your peripheral vision. Also, if the driver isn't expecting to enter an occupied platform (it doesn't show on the diagram unless you're due to attach), he or she may be calling the signaller to confirm the available platform length. Then there's the whole getting-the-train-moving procedure which can take a good 10-15 seconds.

Understood completely, and, of course, drivers are human. However, the point is that we (the passengers) are repeatedly told (by TOCs replying to complaints of connections missed by a few seconds, whether they are recognised as such or not) that every second counts on the busy railway and for that reason connections cannot be held even for 10-15 seconds (cross-platform) at Redhill (and other places). However, the same discipline appears not to apply often enough to, for example, drivers and signallers.

In the Redhill case, the train in question has been diagrammed to arrive 'on top' of another one since the 11 July emergency timetable was introduced (and quite often prior to that as well), so the shunt indication has been the expected one for two months now. I would expect a driver to be looking at the white lights in anticipation of this. The available platform length is the standard half platform (1A) section, with 1B occupied by the other unit - the standard and very frequent procedure at Redhill.

Anyway, not to overplay this further, I appreciate that this is not the core of the thread, i.e. train speed vs. limits when late.

 

[ComUtoR]

In the Redhill case, the train in question has been diagrammed to arrive 'on top' of another one since the 11 July emergency timetable was introduced

On whose diagram ? The Drivers ? Does the Drivers diagram have permissive working shown or do they have "AP" diagrammed ? Are you sure that the Drivers diagram shows that they are expected to go on top of another unit.

so the shunt indication has been the expected one for two months now.

Expected by who ? Again, you may use this route and service each and every day but as a Driver I may not see a diagram for months and months and it may even be the first time I have been on that diagram. For the Driver it may possibly be the first time they have worked that diagram. If I get permissive working where its not expected then I'm ringing the box.

I would expect a driver to be looking at the white lights in anticipation of this.

Do you drive trains ? You have a lot of expectations about how we should drive but they are very wide of the mark. Anticipating signals leads to a SPAD. Its a very bad thing to do. If I get a Red then I stop at the Red. Not expect permissive working.

The available platform length is the standard half platform (1A) section, with 1B occupied by the other unit - the standard and very frequent procedure at Redhill.

What is the platform length in metres and what is the platform length in coaches for each unit type ? What is the length of 1A and what is the length of 1B. What is the "standard length ? Do they use the new stop short bat/indicator at Redhil ?

Anyway, not to overplay this further, I appreciate that this is not the core of the thread, i.e. train speed vs. limits when late.

It is the very core of this debate. How we drive our units directly reflects on the timetable. One of the arguments in favour of ATO is that units are driven universally. How Drivers behave when getting restrictive aspects will have a direct impact on the timetable. My behaviour towards an approach controlled signal differs from other Drivers and on the routes I drive there are many approach controlled signals. Should I bolt up to them expecting they clear or should I act cautiously and prepare to stop. The signal will typically clear when I come to a stand and from an outside perspective it may appear that I'm not paying attention or deliberately stopped, or the signal cleared slowly, and that I should have been expecting it to clear because its been that way for months; if not years.

 

[Sunset route]

In the Redhill case, the train in question has been diagrammed to arrive 'on top' of another one since the 11 July emergency timetable was introduced (and quite often prior to that as well), so the shunt indication has been the expected one for two months now. I would expect a driver to be looking at the white lights in anticipation of this. The available platform length is the standard half platform (1A) section, with 1B occupied by the other unit - the standard and very frequent procedure at Redhill.

As I've already said above the subsidiary route (calling on not shunt) for T492 siganl at Redhill from the up reading line into platforms one and two that are already occupied has to be of the most severe and restricted approach releases that I've ever known. When the route has been set the berth track circuit has to be occupied for nearly two minutes* before it will allow the subsidiary signal to show a proceed, this is because of the falling gradient on a severe blind curve.

*after checking the locking charts it's 105 seconds once the berth track circuit is occupied when going into an occupied platform.

 

[Deepgreen]

As I've already said above the subsidiary route (calling on not shunt) for T492 siganl at Redhill from the up reading line into platforms one and two that are already occupied has to be of the most severe and restricted approach releases that I've ever known. When the route has been set the berth track circuit has to be occupied for nearly two minutes* before it will allow the subsidiary signal to show a proceed, this is because of the falling gradient on a severe blind curve.

*after checking the locking charts it's 105 seconds once the berth track circuit is occupied when going into an occupied platform.

Interesting. We were held there for over three minutes this morning and the previous movement from any part of platform 1 was ten minutes previously (today's driver was spot on and off the mark immediately), but we were still 3L at Redhill, having been on time previously. I had also assumed that a set time has to elapse before clearing the call-on, but about three weeks ago, we received the call-on aspect before we had even come to a stand, so that blew that theory away (for me, at least).
--- old post above --- --- new post below ---

On whose diagram ? The Drivers ? Does the Drivers diagram have permissive working shown or do they have "AP" diagrammed ? Are you sure that the Drivers diagram shows that they are expected to go on top of another unit.



Expected by who ? Again, you may use this route and service each and every day but as a Driver I may not see a diagram for months and months and it may even be the first time I have been on that diagram. For the Driver it may possibly be the first time they have worked that diagram. If I get permissive working where its not expected then I'm ringing the box.



Do you drive trains ? You have a lot of expectations about how we should drive but they are very wide of the mark. Anticipating signals leads to a SPAD. Its a very bad thing to do. If I get a Red then I stop at the Red. Not expect permissive working.



What is the platform length in metres and what is the platform length in coaches for each unit type ? What is the length of 1A and what is the length of 1B. What is the "standard length ? Do they use the new stop short bat/indicator at Redhil ?



It is the very core of this debate. How we drive our units directly reflects on the timetable. One of the arguments in favour of ATO is that units are driven universally. How Drivers behave when getting restrictive aspects will have a direct impact on the timetable. My behaviour towards an approach controlled signal differs from other Drivers and on the routes I drive there are many approach controlled signals. Should I bolt up to them expecting they clear or should I act cautiously and prepare to stop. The signal will typically clear when I come to a stand and from an outside perspective it may appear that I'm not paying attention or deliberately stopped, or the signal cleared slowly, and that I should have been expecting it to clear because its been that way for months; if not years.

I don't drive trains, and, of course, it's taken as read that anticipating signals to the point of triggering a SPAD would be ridiculous, but responding to cleared ones appropriately is a completely different matter. Obviously, also, there is no other course of action than to come to a stand at a red, no matter how confident one may be of a clearance. I am by no means impugning the drivers' profession, by the way, but in all roles there are mixes of quality. This morning's driver response time was exemplary, but the signal clearance time of around 190 seconds was not.

Anyway, with Southern claiming that they will reinstate the full Redhill timetable from Monday, the problem should reduce hugely, as the Reigate-Tonbridge working will not then be occupying platform 1A, meaning no call-on will be needed. As an aside, given Southern's inability to operate even the emergency timetable (still numerous cancellations against the emergency 'reliable' timetable owing to a shortage of train crews last week and this), I have grave doubts over their claim of full reinstatement!

 

[hounddog]

I know it's a bit late, but to address Deepgreen's comments about the Redhill area:

It's easy to miss the subsidiary signal if you're not looking directly at it. If, for example, you're checking your diagram or taking a drink of water/tea/etc then until you look back up at the signal you may not notice the two little white lights next to the big bright red.

Isn't the whole point of route knowledge that you don't check your diagram or take a drink when approaching such a tricky signal?

 

[contrad!ction]

Interesting. We were held there for over three minutes this morning and the previous movement from any part of platform 1 was ten minutes previously

I think you're missing a train - the up Tonbridge to Reigate that you platform share with arrived in at 0828 2L into P1 (booked to be 0826) which is what I suspect has been delaying you the past few weeks.

 

[Deepgreen]

Isn't the whole point of route knowledge that you don't check your diagram or take a drink when approaching such a tricky signal?

That's what I would have assumed/hoped, as well.
--- old post above --- --- new post below ---

I think you're missing a train - the up Tonbridge to Reigate that you platform share with arrived in at 0828 2L into P1 (booked to be 0826) which is what I suspect has been delaying you the past few weeks.

Quite right - I overlooked that late-running move - apologies. However, does it need a two-or-so minutes gap between that arrival and the call-on being cleared, given that the GWR train had already been occupying its circuit for the required 105 seconds? I did comment at the time of the emergency timetable introduction that the timing of the ex-Tonbridge arrival would be likely to cause conflict if running only a small amount late.

Anyway, let's hope it resolves from Monday.

 

[najaB]

Isn't the whole point of route knowledge that you don't check your diagram or take a drink when approaching such a tricky signal?

As I read things (and I'm not a driver) it isn't 'tricky' at all. You approach the signal at red and stop, as for any other signal. The only 'trick' to it is noticing the calling on signal lighting up *after* you're already stopped. Unlike a red to yellow change, it isn't obvious unless you're looking directly at it and it's not reasonable to expect a driver to be staring at a red signal constantly.

 

[Deepgreen]

As I read things (and I'm not a driver) it isn't 'tricky' at all. You approach the signal at red and stop, as for any other signal. The only 'trick' to it is noticing the calling on signal lighting up *after* you're already stopped. Unlike a red to yellow change, it isn't obvious unless you're looking directly at it and it's not reasonable to expect a driver to be staring at a red signal constantly.

I agree that there is no trickiness about it, but disagree that it is unreasonable for a driver to look (not "stare") at or near to the signal when awaiting a change - and also point out that these call-on lights are bright white LED ones, at driver's eye level and are accompanied by an illuminated platform number above the signal head. Even in peripheral vision, these three lights should register easily enough.

 

[najaB]

I agree that there is no trickiness about it, but disagree that it is unreasonable for a driver to look (not "stare") at or near to the signal when awaiting a change...

But hounddog's post to which you referred spoke about approaching a 'tricky' signal and seemed to indicate that you think that they shouldn't take their eyes off the signal even momentarily to check anything else (e.g. their diagram).

 

[SpacePhoenix]

Where a signal has a call-on signal as well, will there be a short seprate track circuit just by the signal?

 

[Clip]

I agree that there is no trickiness about it, but disagree that it is unreasonable for a driver to look (not "stare") at or near to the signal when awaiting a change - and also point out that these call-on lights are bright white LED ones, at driver's eye level and are accompanied by an illuminated platform number above the signal head. Even in peripheral vision, these three lights should register easily enough.

That red signal may have been the only time where the driver has been able to grab a quick glace at their diagram or have a bit of refreshment for some time and I would never begrudge them missing the call on instanlty for that.

 

[Deepgreen]

But hounddog's post to which you referred spoke about approaching a 'tricky' signal and seemed to indicate that you think that they shouldn't take their eyes off the signal even momentarily to check anything else (e.g. their diagram).

I agreed with Hounddog's view concerning route knowledge and all that entails, including it possibly being inappropriate to check a diagram or drink at such a time (if doing so compromises attention to the signal), yes, especially when so close to a terminus when there will be time during the turn-round to do these things, or when not needing to pay attention to a red signal. My peripheral vision comment also still stands - i.e. that it shouldn't be necessary to stare fixedly directly at a signal to notice a change occur.