Why doesn't Southeastern use 300 km/h trains for its domestic high-speed operation?

[miklcct]

The HS1 is built to 300 km/h but Southeastern only uses 225 km/h train for its domestic routes. Why doesn't Southeastern use 300 km/h trains instead?

 

[duncombec]

I'd suggest the timetable has something to do with it: https://timetables.southeasternrailway.co.uk/#/timetables/851/Table 8

St Pancras to Stratford: 7 minutes
Stratford to Ebbsfleet: 10 minutes (where the North Kent trains exit High Speed running back onto regular tracks)
Ebbsfleet to Ashford: 21 minutes (where other domestic services exit onto regular tracks).

A random internet calculator (https://www.countcalculate.com/cars-and-speed/time-savings-at-increased-speed) tells me even over the longest section (Ebbsfleet to Ashford, 33 miles) the maximum gain would be 3.5 minutes, some of which would be lost through acceleration and deceleration. (Other distance are 0.64 minutes and 1.8 minutes).

 

[mmh]

I'd suggest the timetable has something to do with it: https://timetables.southeasternrailway.co.uk/#/timetables/851/Table 8

St Pancras to Stratford: 7 minutes
Stratford to Ebbsfleet: 10 minutes (where the North Kent trains exit High Speed running back onto regular tracks)
Ebbsfleet to Ashford: 21 minutes (where other domestic services exit onto regular tracks).

A random internet calculator (https://www.countcalculate.com/cars-and-speed/time-savings-at-increased-speed) tells me even over the longest section (Ebbsfleet to Ashford, 33 miles) the maximum gain would be 3.5 minutes, some of which would be lost through acceleration and deceleration. (Other distance are 0.64 minutes and 1.8 minutes).

Plus St Pancras to Ebbsfleet is 230km/h maximum signalled speed if I remember right, so the amount of higher speed running potentially available is tiny and very expensive for next to no advantage.

 

[hexagon789]

Plus St Pancras to Ebbsfleet is 230km/h maximum signalled speed if I remember right, so the amount of higher speed running potentially available is tiny and very expensive for next to no advantage.

Towards the Channel Tunnel:
230km/h to Southfleet
300km/h after Southfleet
With a 270 restriction through Ashford iirc.

So yes, relatively little point in having 300km/h capable domestic HS1 trains.

 

[eastwestdivide]

Does the fact that they also have to perform much of their duties on far lower-speed lines have any bearing on their configured max speed?

 

[popeter45]

on HS1 i feel like per train capacity would be far more useful than higher speeds
if throwing about crayons about gauge expansion on parts of SE's classic lines somthing like 230km/h capable double decker trains like a twindexx express would work far better than 300km/h trains

 

[507020]

on HS1 i feel like per train capacity would be far more useful than higher speeds
if throwing about crayons about gauge expansion on parts of SE's classic lines somthing like 230km/h capable double decker trains like a twindexx express would work far better than 300km/h trains

Has loading gauge expansion ever been attempted before? Surely it could be done using a large enough crayon.

 

[swt_passenger]

Has loading gauge expansion ever been attempted before? Surely it could be done using a large enough crayon.

Ah, are you suggesting forcing a very large crayon through the tunnels?

 

[hexagon789]

Does the fact that they also have to perform much of their duties on far lower-speed lines have any bearing on their configured max speed?

Perhaps directly, perhaps secondarily.

There is after all not much point having 300km/h gearing when traction current draw is limited enough reducing performance on 750V dc as it is, I believe the 395s are more lethargic than the Electrostars on dc? (Perhaps someone can confirm/refute)

 

[507020]

Ah, are you suggesting forcing a very large crayon through the tunnels?

Yes

 

[Bald Rick]

The HS1 is built to 300 km/h but Southeastern only uses 225 km/h train for its domestic routes. Why doesn't Southeastern use 300 km/h trains instead?

as others have said, HS1 is not built to 300km/h for the section that the Javelins do most of their mileage.

The difference in running time between Ebbsfleet and Ashford, stop to stop, between a train with vmax 225 and one with vmax 300 is a little under 2 minutes. The trains would be doing 300km/h for less than 5% of their diagrammed day.

Therefore spending rather a lot more on a fleet of 300 km/h trains to save 2 minutes is clearly not good economic sense.

 

[cle]

They'd be far more useful if Ebbsfleet-Rochester (-Margate) was upgraded! Or the Ashford-Ramsgate stretch, which I think was actually planned for speed uplifts once upon a time.

 

[Bald Rick]

They'd be far more useful if Ebbsfleet-Rochester (-Margate) was upgraded! Or the Ashford-Ramsgate stretch, which I think was actually planned for speed uplifts once upon a time.

not to 300km/h !!! Or even half that.

 

[Peregrine 4903]

It was actually recently found that Class 395's are often slower than Class 375's on the classic routes, so you wouldn't even get a journey time improvement.

 

[cle]

not to 300km/h !!! Or even half that.

Nope, a princely 90mph I recall.

 

[notadriver]

It was actually recently found that Class 395's are often slower than Class 375's on the classic routes, so you wouldn't even get a journey time improvement.

You have no idea (!) lol

 

[zwk500]

They'd be far more useful if Ebbsfleet-Rochester (-Margate) was upgraded! Or the Ashford-Ramsgate stretch, which I think was actually planned for speed uplifts once upon a time.

Isn't Ashford-Ramsgate via Canterbury proposed for Linespeed enhancements to offset the time penalty of stopping at Thanet Parkway?

 

[MattRat]

HS1 gets used to it's full potential from Eurostar, it's potential isn't being wasted, and given the cost of a faster train, especially one that fits our tiny loading guage, it just isn't worth it.

Unless you are somehow suggesting Eurostar will fail and then the line won't be used to it's full potential?

 

[Jturner98]

Isn't Ashford-Ramsgate via Canterbury proposed for Linespeed enhancements to offset the time penalty of stopping at Thanet Parkway?

Yes although they don’t know where the linespeed will be increased yet

 

[SolomonSouth]

I believe the 395s are more lethargic than the Electrostars on dc? (Perhaps someone can confirm/refute)

Yes. A 375 will hit 60mph in 70 seconds compared to around 75 seconds for the 395. Up to 100 - the 375 will be around 5 minutes but the 395 cannot hit 100 on a flat track.

Having said that, I did some measuring with GPS, and from 0-50mph, I can't see much difference between 375 and 395. In most cases the difference isn't that much - 395s can just as easily keep to schedule or arrive early on the Kent Coast line as 375s - and they do seem to slip less in wet conditions so that is a plus.

 

[hexagon789]

I

Yes. A 375 will hit 60mph in 70 seconds compared to around 75 seconds for the 395. Up to 100 - the 375 will be around 5 minutes but the 395 cannot hit 100 on a flat track.

Having said that, I did some measuring with GPS, and from 0-50mph, I can't see much difference between 375 and 395. In most cases the difference isn't that much - 395s can just as easily keep to schedule or arrive early on the Kent Coast line as 375s - and they do seem to slip less in wet conditions so that is a plus.

I suppose the 395 does have the advantage of all-motored intermediate cars.

 

[mmh]

HS1 gets used to it's full potential from Eurostar, it's potential isn't being wasted, and given the cost of a faster train, especially one that fits our tiny loading guage, it just isn't worth it.

That's just not true. It's very, very underused and always has been.

 

[notadriver]

Yes although they don’t know where the linespeed will be increased yet

I would guess a raising of the overall line speed to 80 mph from 70 and a higher speed (maybe 60 mph vice 40 mph) going through Grove Ferry.

 

[MattRat]

That's just not true. It's very, very underused and always has been.

I meant in terms of speed limits. Eurostar goes at the maximum line speed. And even without Eurostar, the only cost effective solution for SE would be class 373s, although those would be considered a downgrade to the average passenger due to age.

 

[notadriver]

Yes. A 375 will hit 60mph in 70 seconds compared to around 75 seconds for the 395. Up to 100 - the 375 will be around 5 minutes but the 395 cannot hit 100 on a flat track.

Having said that, I did some measuring with GPS, and from 0-50mph, I can't see much difference between 375 and 395. In most cases the difference isn't that much - 395s can just as easily keep to schedule or arrive early on the Kent Coast line as 375s - and they do seem to slip less in wet conditions so that is a plus.

More like 80 seconds for a 395 to 60mph. And above 50 mph is where the differences are noticeable.

 

[SolomonSouth]

The 395s are also slower than 465/9s which sometimes run interchangeably with 375s - the 465/9 manages a 59 second 0-60.

The 395s are also slower than 465/9s which sometimes run interchangeably with 375s - the 465/9 manages a 59 second 0-60.

The 465/9 is very fast even with only 2/4 powered coaches. Then again you are almost going nowhere in the wet.