Station Approach Speeds

[Deepgreen]

I had inserted a few comments about station approach speeds as an aside in the GTR Industrial Action thread, but it's probably better to have a separate thread.

The Betchworth example I cited (where drivers routinely encounter a red starter signal at the station, protecting the level crossing) was mentioned in the other thread.

My point was that some drivers seem to approach the signal with extreme caution (the approach is on a long rising gradient of 1 in 144), bringing the train down to less than 5mph while still at least ten train lengths out of the station, on wet or dry rails.

Now; there are some who don't exercise such extreme caution, but who approach the station and the red starter signal at what I would deem a sensible speed (around 10-15mph entering the platform), again on wet or dry rails.

This is certainly not about criticising drivers, who will rightly do as they are instructed, but I am interested to know how this significant variation in techniques is accounted for in timetabling. The North Downs line has many stations where level crossings are at platform ends, and it is common/dare I say normal to find trains leaving, say, Reading, on time, and losing a minute here and there, until arriving at Redhill almost ten late, with no apparent delay cause en route.

If the 'extreme caution' approach is that which drivers are instructed to adopt, surely the timetable needs to reflect that? The converse has, by the way, just been applied, with a minute being shaved off departure times at Betchworth and Reigate. Since this happened it has been even rarer to find trains keeping good time. It appears that the timetabling does not reflect the driving technique required, but I seek views on that.

Incidentally, the interlocking with Buckland crossing for stopping trains at Betchworth is understood, but this morning saw an uncommon example where the approaching 0818 stopping train (running only two minutes late) was given the green signal well before it even came into view, which must have closed Buckland crossing for at least five minutes. Even for trains with more severe late running, this signal clearance before the train is actually at the platform is still rare.

 

[II]

Some driver do exercise a little too much caution IMHO - not necessarily a criticism, just the way new hands are taught as he advice and instructions drivers have to adhere to get more and more stringent as the years go by, to try and reduce even further the number of operational incidents. I think in certain instances they have gone too far though, and certainly the driving you describe sounds excessively slow, on a dry rail at least.

Managers are certainly very hesitant on criticising driving that is very slow as a rule for obvious reasons.

 

[The Planner]

Sometimes you cannot alter the timetable without it breaking and often if you do want to alter it to reflect reality the TOC will refuse.

 

[Deepgreen]

Sometimes you cannot alter the timetable without it breaking and often if you do want to alter it to reflect reality the TOC will refuse.

Quite, but in this case, the timetable has been altered, but to reduce times, rather than allow for more cautious driving! There has to be the right balance between timetable and caution. The timetable on the North Downs line has remained essentially the same for years, but drivers' caution seems to be increasing all the while. At what point, I wonder, does the latter in itself 'break' the timetable?

 

[Bald Rick]

Quite, but in this case, the timetable has been altered, but to reduce times, rather than allow for more cautious driving! There has to be the right balance between timetable and caution. The timetable on the North Downs line has remained essentially the same for years, but drivers' caution seems to be increasing all the while. At what point, I wonder, does the latter in itself 'break' the timetable?

Personal view - this is the single largest factor why underlying performance on Southern has been declining for the last decade.

I have observed similar wide variations on Thameslink, for example approaching West Hampstead S Jn on the UF with the route set for the US. Some drivers brake at the first sight of the flashing yellows, are doing 50 from Cricklewood all the way to West Hampstead, where the steady single yellow with feather clears to green on approach, and take the junction at 50. (Some even take the junction at 40, which it is Northbound, but it is 50 southbound).

Other drivers see the flashing yellows, brake after Cricklewood, doing about 60 whether junction signal clears up to green, accelerate back up to about 75 through West Hampstead, brake for 50 for the junction.

The latter is about 30-40 seconds quicker, and is what the timetable is based on. Most frustrating.

 

[Tomnick]

Incidentally, the interlocking with Buckland crossing for stopping trains at Betchworth is understood, but this morning saw an uncommon example where the approaching 0818 stopping train (running only two minutes late) was given the green signal well before it even came into view, which must have closed Buckland crossing for at least five minutes. Even for trains with more severe late running, this signal clearance before the train is actually at the platform is still rare.

Just to clarify, in that case, the sequence at Buckland AHB won't start until the train reaches the normal 'strike in' treadles, which will be a little way - a few hundred yards or less, at a guess - in rear of Betchworth station. It's only if the train strikes in before the signal is cleared (or is held at danger by 'stopping' controls) that the crossing sequence is suppressed until the signal is ready to clear, and the signal prevented from actually clearing until the crossing sequence has been running for a predetermined period of time.

 

[The Planner]

Personal view - this is the single largest factor why underlying performance on Southern has been declining for the last decade.

I would replace Southern with everywhere if it were me.

 

[louis97]

Personal view - this is the single largest factor why underlying performance on Southern has been declining for the last decade.

I have observed similar wide variations on Thameslink, for example approaching West Hampstead S Jn on the UF with the route set for the US. Some drivers brake at the first sight of the flashing yellows, are doing 50 from Cricklewood all the way to West Hampstead, where the steady single yellow with feather clears to green on approach, and take the junction at 50. (Some even take the junction at 40, which it is Northbound, but it is 50 southbound).

Other drivers see the flashing yellows, brake after Cricklewood, doing about 60 whether junction signal clears up to green, accelerate back up to about 75 through West Hampstead, brake for 50 for the junction.

The latter is about 30-40 seconds quicker, and is what the timetable is based on. Most frustrating.

Don't forget at present, and as has been there for a few months now (maybe longer?), there is a 50mph TSR over Cricklewood South Junction.

 

[ComUtoR]

I have observed similar wide variations on Thameslink, for example approaching West Hampstead S Jn on the UF with the route set for the US.

The differences could be down to when the junction is cleared as well as when it steps up. Unless it steps up then I'd be reducing my train down to 20 mph for the red anyway.

The timetable is broken in more ways than defensive driving. My path yesterday was clearly timetabled to receive the !"£!""£$£" number of reds I had. My path was behind an ECS service.

If I ever met a planner in real life I don't think we'd get on. The question is; should the planners time the units based on what they perceive to be the correct driving method and are they willing to mandate that style in PDPs or should real world driving be reflected in the planning. I drive too many routes that are poorly timed to care about the timetable any more. I am guaranteed to be late at specific stations no matter how defensive or aggressive I drive.

 

[Bald Rick]

The differences could be down to when the junction is cleared as well as when it steps up. Unless it steps up then I'd be reducing my train down to 20 mph for the red anyway.

It's exactly the same signal sequence - it's a left hand bend all the way and you can see the signals from the passenger compartment.

As an aside, in this instance the junction signal steps up to Green (from single yellow) when the train is at least 400metres away. Are you saying that you would be down to 20mph that far back ? (It's not a criticism, I'm genuinely interested).

However I had forgotten the 50TSR at Cricklewood, however some drivers speed up after it with proceed aspects, and some don't.

 

[ComUtoR]

It's exactly the same signal sequence - it's a left hand bend all the way and you can see the signals from the passenger compartment.

It's not exactly the same. At least from my perspective. What can happen is that you get 2 solid before it steps up to 2 flashing and not always at the same place/time. It's also possible to go past the two yellows before it steps up. If you stood there every day, all day for a month you would see the small variations that we pick up on as Driver who do this day in and day out.

As an aside, in this instance the junction signal steps up to Green (from single yellow) when the train is at least 400metres away. Are you saying that you would be down to 20mph that far back ? (It's not a criticism, I'm genuinely interested).

The sequence is 2 flashing, 1 flashing, 1 solid + indicator, expect red. Because its checking you down to a red I'm still expecting to stop at a red after receiving a single yellow. I need to have an intention to stop. I'm not doing 20 that far back but I am decelerating. When it steps up then I'd then make a decision based on what indication I get. I do that for almost every single flashing yellow junction I go through. I'm also a bit more "new school" and drive defensively. That has come with experience and learning the hard way.

If you can guarantee it will 100% step up to green then I'd drive differently but I must ensure that I allow for the red.

I do the same on an approach control signal. I must allow for the signal to remain at red regardless of it clearing at the same point and same timing each time.

There are some of our approach control signals and various checking down, junction indications that are determined by what's on the other line. Some days you get the typical sequencing and the signal clears at the same point and other days your held and others your stepped green as the service on the adjacent line has long cleared.

Signals do weird and wonderful things but single yellow means expect red on the next one. So, we drive accordingly.

Even when the timetable allows for such working you still are at the mercy of timings at stations etc that are impossible to make.

As an example. We have a diagram where the same trip is timed with 4 different times. Where the fork do the minutes suddenly vanish to and how can you be expected to maintain the timetable when the same stopping pattern gets different timings.

I think we have both discussed before about padding and real world timings. My biggest bugbear of a route for delays reflects pretty much every timetable/planning problem I know of in a single trip. If they timed it at XX minutes instead of XY the service would almost never be late.

As an aside, when we moved towards RTR instead of PPM the daily figures really do show how poorly we run trains and how poor the timetable really is. Deepgreen and I rarely see eye to eye but he gets a little support here from me in that the timetable can be frustrating as hell and doesn't reflect reality. I can feel his frustration about constantly dropping a single minute.

 

[Bald Rick]

It's not exactly the same.

Sorry, I'm not arguing with you here. I know the signal sequences can vary at the same location (including W Hampstead South Jn) depending on what the signaller does.

However in the examples I quoted the sequence was exactly the same, as I was watching it. They happened last week, on the same timetabled service, on successive days, with exactly the same sequence. In one example, I could see the junction signal had cleared to green and the driver then accelerated until the braking point for the junction. In the other, I could see the signal had cleared to green, and the driver didn't accelerate, and stayed at 50 (and coasting). The difference in these examples is entirely on green signals, and that's the bit I don't get.

Clearly, you always have to expect that a caution aspect is going to lead to a red, and drive accordingly. However I do have a possibly controversial view that successive changes to Professional Driving Policy have led drivers to be more cautious than they need to be in some circumstances, particularly at low speed, and particularly given TPWS.

 

[ComUtoR]

Sorry, I'm not arguing with you here. I know the signal sequences can vary at the same location (including W Hampstead South Jn) depending on what the signaller does.

Then consider this. If, as a Driver, I don't see that same sequence and that I go through this junction, and others, on a regular basis. Should I drive expecting the same sequence or drive expecting the unexpected ? Because, that is what's happening. You may see the same sequence but I don't so I drive it differently. I am also driving it differently to others. However, my approach is consistent. So what your also seeing is different Drivers doing what they do. It may be a case where if you saw the same sequence and the same Driver then it would be much more consistent. Same unit type, weather etc ?

and the driver didn't accelerate, and stayed at 50 (and coasting). The difference in these examples is entirely on green signals, and that's the bit I don't get.

My perspective is that the second Driver is driving much more efficiently. If I know the junction is 50 and the sequence is restricted (it is restricted when you first see it) then hit 50 and coast is pretty perfect. Why accelerate only to brake a short time after ? it seems wasteful. Plus if I can keep my speed through the initial restriction before it steps to green I might find that I never have to worry about the red if it doesn't step up. I hit 50, coast, signal steps up, right speed for the junction, power out and into Belsize.

Incidentally, do they arrive on time at St Pancras ?

It's difficult to comment on styles as I see it more as a whole and not from a single junction. If your already on restrictive signals then that will also determine what brake step or power to use Also, if your running late/early etc. I am making many decisions on how to drive based on numerous factors and not just the signal sequence.

Clearly, you always have to expect that a caution aspect is going to lead to a red, and drive accordingly.

Yep and I have never really understood high speed junctions as you are always checked down to a red so you can keep a fast approach but still need to prepare to brake OR (and this is what your seeing I suspect) slow on approach and coast through and time it just right. I know where I can time it just perfectly so that I maintain my speed just perfectly right to the point in which a signal typically steps up.

However I do have a possibly controversial view that successive changes to Professional Driving Policy have led drivers to be more cautious than they need to be in some circumstances, particularly at low speed,

The railway moves at a glacial pace and for me, I think the planners are the ones who are behind the times here. The PDPs have come about due to incidents and has helped to reduce and mitigate risk. I certainly believe that whilst restrictive at times, they are important to the safe running of the railway. The days of charging round at max effort all the time are long gone.

I would also controversially state that unless the timetable reflected genuine times between stations and timings that were actually achievable then its difficult to place blame on the PDP themselves.

We also have a couple of places where the line-speed has been reduced but the timings haven't changed. Guess what, we are late at destination.

and particularly given TPWS.

TPWS interventions are costing Drivers their jobs. You can understand why they are defensive driving. Could you clarify what you meant by that statement please. I'm a little hesitant on how to reply and what direction your coming from. Cheers.

Another little curveball to throw out there is that I only see my timings for stations. We used to have the junction path times listed on the schedule but they were taken off. We both know that there will be a pathway across a specific junction but from my perspective, and newer Drivers, I get to destination on time and whatever happens in between is insignificant. I only see the service as on time. I'm lucky as I've been around a while so I understand it a bit better but our new Drivers just see a schedule with stations and their times next to it. Our delays are also only really asked about between stations too.

If we move permanently to Right Time I think the timetable will change. We have had a few minutes inserted but I think they get put in as <> time (I think that's the right one) but the next timetable change and we are back to square one.


*random thought edit*
At West Hampstead and other flashing junctions. If the route is clear and its a high speed junction why not just route the entire thing at green ? Or use PRIs ? Is it also a case of the signalling system is also too restrictive ?


Permanent changes to reflect actual running time is what is needed.

 

[Rich McLean]

No idea if this applies in this case but the Driver Advisory System (DAS) often tells you different things on what appears to be under the same signal sequence. So while you can see the same aspect sequence, DAS may kick in on the Monday to advise to coast if there is a booked move a few blocks ahead, and on Tuesday will tell the driver different advice if sections ahead are clear as an example so would advise power application. As a passenger you wouldn't have this information.

 

[philthetube]

wrong quote

 

[philthetube]

Sorry, I'm not arguing with you here. I know the signal sequences can vary at the same location (including W Hampstead South Jn) depending on what the signaller does.

However in the examples I quoted the sequence was exactly the same, as I was watching it. They happened last week, on the same timetabled service, on successive days, with exactly the same sequence. In one example, I could see the junction signal had cleared to green and the driver then accelerated until the braking point for the junction. In the other, I could see the signal had cleared to green, and the driver didn't accelerate, and stayed at 50 (and coasting). The difference in these examples is entirely on green signals, and that's the bit I don't get.

Clearly, you always have to expect that a caution aspect is going to lead to a red, and drive accordingly. However I do have a possibly controversial view that successive changes to Professional Driving Policy have led drivers to be more cautious than they need to be in some circumstances, particularly at low speed, and particularly given TPWS.

Were both trains running to time?

Did both arrive at the next station on time, subject to other delays?

The time difference between accelerating and then braking compared with coasting over a mile is negligible and if the answers to the above questions are yes then the second driver should be praised, if causing delays that is different.

 

[Bald Rick]

Were both trains running to time?

Did both arrive at the next station on time, subject to other delays?

The time difference between accelerating and then braking compared with coasting over a mile is negligible and if the answers to the above questions are yes then the second driver should be praised, if causing delays that is different.

No x 2, both were late and both arrived late at St Pancras.

The time loss when coasting for over a mile is not negligible, if you have the opportunity to get up to 75/80 mph in the interim. It costs about 30 seconds. And when the railway is at capacity, every second counts.

ComUtoR: I agree it's different drivers driving to different styles, and that is the basis of my question.

Re TPWS. I know drivers are losing their jobs (occasionally) through TPWS activations. But that is a function of the more conservative PDP. What I meant is, for example, London Bridge terminal platforms. The TPWS for the bufferstops is set for 12.5mph. IIRC, Southern's PDP requires drivers to be doing no more this 6mph at the grids (it might be 8mph). This is in case the speedo is reading low, with a further margin for error. Some drivers will have been taught to treat that 6 or 8 mph with further caution and come in under that. Which leads to 12 coach trains crawling at little more than walking pace for the last 100m to the stops, with the back end locking the throat. In some cases drivers need to accelerate to get to the stops, which surely can't be the right thing to do!

But the thing is, the grids are deliberately set to be cautious themselves. if a train went over those grids at 20mph, it would stop in about 45metres, ie well before the buffer stops.

My point is that the TPWS is set at a cautious level, the PDP adds another layer of caution, and then drivers are taught to add a further layer over that. This is not to point the finger at drivers in any way. Nobody can blame a driver for doing what he or she has been taught to do. However I don't believe it makes the railway safer.

As an aside, whenever NR tries to alter the sectional running times to reflect the PDP, the TOCs invariable say get stuffed. There are parts of South London where if the timetable accurately reflected real world dwell and running times, we'd be chopping out 10-20% of the peak service.

 

[The Planner]

As an aside, whenever NR tries to alter the sectional running times to reflect the PDP, the TOCs invariable say get stuffed. There are parts of South London where if the timetable accurately reflected real world dwell and running times, we'd be chopping out 10-20% of the peak service.

This, if we try to correct things to reflect what happens (and we can only best guess PDP as TOCs generally wont share it) and increase journey times we are told where to go as it affects the TOCs bottom line. All very well moaning at us but if your lords and masters dont want to play ball then what do you want us to do?

 

[ComUtoR]

No x 2, both were late and both arrived late at St Pancras.

If we are really trying to find the root cause of the delay then do you know by chance what the path at West Hampstead is and if both services passed the junction on time. ? From my perspective my time at St Pancras is more relevant because that is where I am booked to be and that is where the passengers need us to be on time. From a timetable perspective then the timing across the junction is the critical point.

ComUtoR: I agree it's different drivers driving to different styles, and that is the basis of my question.

The time loss when coasting for over a mile is not negligible, if you have the opportunity to get up to 75/80 mph in the interim. It costs about 30 seconds. And when the railway is at capacity, every second counts.

The time difference between accelerating and then braking compared with coasting over a mile is negligible and if the answers to the above questions are yes then the second driver should be praised, if causing delays that is different.

I see it from phil's point. The second Driver I think, done a better job. He maintained good control, was ECO driving, displayed workload management NTS, and was smoother for passenger comfort. Driving style does not affect the timetable that we see. If both services were late at St Pancras then it didn't make any difference so why drive aggressively ? Personally the skill in driving sometimes does lie in how well your able to coast and maintain your speed but still maintain the timetable.

I remember when a certain new traction was introduced and the aggressive driving style meant that Drivers were arriving early at stations. SO they adapted and didn't push the limit so much. That would appear to be driving 'slow" for the sake of a PDP but in reality we are still running to the timetable, just taking less effort to do it.

When you push linespeed to the max your accelerating then braking. The same times can be maintained by coasting for longer. On long signal sections then I'd lean towards you and say that time can be lost by not pushing the unit to the max but for the most part I see it as negligible. I would also say that we shouldn't have to push to the max each and every time day in day out. The timetable shouldn't be that tight. Its part of the reason why the slightest nudge and the service collapses. I think we have pushed capacity to the limit and its caused more problems than solved.

Re TPWS. I know drivers are losing their jobs (occasionally) through TPWS activations. But that is a function of the more conservative PDP.

A Drivers SOL record is very important. Every activation goes on their records and is treated quite harshly. The function of the TPWS is to prevent/reduce/mitigate against incident. If you trip it then they look to what could of happened not how safe the system is.

What I meant is, for example, London Bridge terminal platforms. The TPWS for the bufferstops is set for 12.5mph. IIRC, Southern's PDP requires drivers to be doing no more this 6mph at the grids (it might be 8mph). This is in case the speedo is reading low, with a further margin for error. Some drivers will have been taught to treat that 6 or 8 mph with further caution and come in under that.

Yeah I do get it but it has all come out of incidents. When I first started we used to drive to the max and knew the speeds of every grid. However, they would trip daily. This is because we pushed the limit so tight that incidents still happened. I can't remember the last starter signal that was passed due to overrun (driver error) This is because those PDP's have been introduced and that error margin has been increased. TPWS stops you in the overlap. TPWS + PDP stops you before the signal. If the PDPs were not successful then I wouldn't support them. Don't get me wrong, some are a pain in the ass and some just nonsensical but the railway doesn't take risks any more. I do agree that some things we do have a negative affect on the timetable but we are adapting, the timetable isn't and that is just as stupid.

However I don't believe it makes the railway safer.

I used to think like that. But then I get shown the stats for incidents and see how much they have been reduced.

As an aside, whenever NR tries to alter the sectional running times to reflect the PDP, the TOCs invariable say get stuffed. There are parts of South London where if the timetable accurately reflected real world dwell and running times, we'd be chopping out 10-20% of the peak service.

I've seen some really stupid timetable decisions and the number of times Drivers have screamed at the management that we need X minutes her, better turnaround times etc but it falls on deaf ears. Money talks in TOC world. The affect on the passenger cannot be forgotten. If your train runs late daily you would be annoyed. If it meets PPM then the TOC pretty much doesn't care. The move to RTR needs t be supported by proper timings so that the bloke on the platform at his local station has a train that arrives on time every day instead of always a minute late.

This, if we try to correct things to reflect what happens (and we can only best guess PDP as TOCs generally wont share it) and increase journey times we are told where to go as it affects the TOCs bottom line. All very well moaning at us but if your lords and masters dont want to play ball then what do you want us to do?

Nobody works together. It really ****s me off

Passengers want quicker journeys but want trains on time. Capacity needs to increase but its past breaking point on some routes. Cheaper to pay compensation to passengers.

 

[Deepgreen]

Were both trains running to time?

Did both arrive at the next station on time, subject to other delays?

The time difference between accelerating and then braking compared with coasting over a mile is negligible and if the answers to the above questions are yes then the second driver should be praised, if causing delays that is different.

Not on 700s it isn't, if they use all their 6600hp! They have been designed with so much power for exactly this reason - to be especially responsive to permit the 24tph core service to be operable.

 

[Deepgreen]

Passengers want quicker journeys but want trains on time. Capacity needs to increase but its past breaking point on some routes. Cheaper to pay compensation to passengers.

I actually think far more passengers would prefer on time trains than would want quicker ones per se - it's reliability and predictability they (I) crave, rather than a few minutes quicker journeys.

Your point about compensation is well made - the culture is established now.

 

[ComUtoR]

Not on 700s it isn't, if they use all their 6600hp! They have been designed with so much power for exactly this reason - to be especially responsive to permit the 24tph core service to be operable.

Metro units accelerate and brake all day long. Quick acceleration should benefit the core but there is a diminishing return on that too. Those of us with experience can find that balance between pushing it and when to go easy. Even with a perfect unit and perfect conditions you often still can't make the next station on time.

Give a passenger a choice between the fast to Cross or the stopper. They will pretty much always choose the faster service. When I get enquired about trips into X location the first words out the passengers mouth is either "when is the next one to" or "what's the quickest one to"

The frustration over delays is how if affects our daily lives. The service is broken almost daily and trains are constantly late. They feel mistreated and rightly so. PPM is a joke and a get out clause for poor scheduling. However I guarantee that a massive percentage of passengers who walk up and go don't know what time its booked across X junction or that its +1 at an intermediate station. If we gave them a choice to cut the service but guarantee trains to be on time they would still chose capacity over timekeeping.

 

[ComUtoR]

Not on 700s it isn't, if they use all their 6600hp!

I tried really hard but I couldn't get one to take full power. We got it there but it shut of and regulated itself. On DC i didn't feel much of a difference between a 319 or a Networker, in fact it felt a little sluggish in comparison.

 

[Deepgreen]

I tried really hard but I couldn't get one to take full power. We got it there but it shut of and regulated itself. On DC i didn't feel much of a difference between a 319 or a Networker, in fact it felt a little sluggish in comparison.

That's interesting - have they been artificially restricted/limited until the full service is introduced/power supply upgrades are finished, I wonder? As part of the core is DC, I would have thought it would need to have comparable performance with AC.

Or perhaps you didn't notice that the dial goes up to 11?!

 

[ComUtoR]

I have no idea what restrictions, if any, have been placed. I doubt any have. But I can say for certain that performance wise there was little difference. I have a personal performance measure for my units where I know how well a unit is doing. It's a direct comparison and the 700 was a touch slower. Much better on brakes though.

On the dial to 11..

There is a power gauge and I only got it to the top once but then it immediately held back the power. A 376 does the same. Hence coasting/accelerating does not affect the timetable as much as you would think.

 

[GusB]

Interesting discussion, but I have a quick question. What is PDP in this context?

 

[Bald Rick]

The 700s are very much restricted on DC (to about half power), and I have been told that they are also restricted (slightly) on the AC. I found the latter hard to believe, but the person who told me would definitely know.

 

[bahnause]

Hence coasting/accelerating does not affect the timetable as much as you would think.

I agree it doesen't affect the timetable much. Energy consumption otherwise is affected a lot. We were tought not to accelerate for a short strech, it's very bad "value for money".

The exclusive use of the regenerative brake is a similar case. We measured the energy consumption on a 45km long 200km/h line with a speed reduction from 200km/h to 160km/h at the end. Using the regenerative brake of the loco and the air brakes of the carriages combined takes 24mins 18secs and uses 841kWh. Using the regenerative brake only takes a mere 5secs more, but reduces energy consumption by 64kWh (-8%). Train weight was around 630tons.

 

[ComUtoR]

Interesting discussion, but I have a quick question. What is PDP in this context?

Professional Driving Policy.

@Hairless Richard. I checked all trains for a random 2 hrs (2x 1hrs) today that went through the junction. The results were quite interesting. Almost every single train made West Hampstead South junction on time and a few were early. Most were on time at St Pancras and a couple of units that were running +1 maintained that delay so no additional time was lost. In the first hour I checked only 1 service was late at St Pancras and that still hit West Hampstead south Jn on time.

@the man with the cunning plan. Cheers for the info for 700's I think its about 70/80% it drops to on DC. Next time I'm in one I'll take a closer note. With 700's through the core aren't most of the time savings gained through boarding efficiencies ?

 

[hwl]

The 700s are very much restricted on DC (to about half power), and I have been told that they are also restricted (slightly) on the AC. I found the latter hard to believe, but the person who told me would definitely know.

The continuous rating of each transformer (12 car) is 2.204MVA so 4.408MVA in total for a total traction motor rating of 5.0MW so an 88% continuous limit on AC might make sense with a short term overload allowed for acceleration???