HS1 vs HS2 speed

[Gadget88]

How come HS2 is planned to go 250 miles per hour but Eurostar is 200? Are the trains going to be more advanced? Could HS1 line handle faster speeds?

 

[Bald Rick]

Simple answer is at HS1 was designed for a ruling maximum of 300km/h (186mph), whilst HS2 is designed for 400km/h (249mph).

Both of these are maximums - there are significant stretches of both lines where the maximum is lower because of infrastructure considerations.

 

[hexagon789]

How come HS2 is planned to go 250 miles per hour but Eurostar is 200? Are the trains going to be more advanced? Could HS1 line handle faster speeds?

HS1 was constructed to support up to 300km/h (186mph) in places, that being the normal maximum for high-speed lines when it was conceived.

HS2 is being designed for 400km/h (249mph); 360km/h (224mph) in service probably because since HS1 opened most new high-speed lines have been built to support more than 300km/h, typically 320km/h and I'd imagine that the higher speed is a degree of future-proofing.

 

[Gadget88]

Cool so will HS1 get the HS2 upgrade? If it did how quick will it get to Paris?

 

[LNW-GW Joint]

Signalling is a constraint.
HS1 was built to the then TGV 300km/h standard with TVM430 signalling - as was the connecting Channel Tunnel and LGV Nord in France.
All new high speed lines are now being equipped with ERTMS/ETCS signalling, and all new rolling stock will support it.
SNCF has a plan to convert its older high speed lines to ETCS, and at the same time to raise line speeds to 320km/h or higher.
That means discarding the first generation of TGVs, so it is keyed to fleet replacement plans.
We will probably do the same with HS1 at some point, but it will be expensive and is not yet on the horizon.
Some parts of HS1 will not be capable of higher speeds, such as in the tunnels and across viaducts.
Journey time reductions would probably be marginal in the UK, but might be more significant in France.
I think the Siemens class 374s will cope with 320km/h, but probably not the Alstom 373s.

 

[hexagon789]

Cool so will HS1 get the HS2 upgrade? If it did how quick will it get to Paris?

I don't think it would make a significant difference to be honest, a greater difference might be made if the line to Ashford was upgraded to 300km/h. It's not a particularly long high-speed line HS1, so I don't think you benefit as much as longer with HSLs.

I think the Siemens class 374s will cope with 320km/h, but probably not the Alstom 37

The 374s are 320 capable, the 373s are only 300 max and being older I doubt they'd ever get upgraded for the higher speed.

 

[Bald Rick]

Cool so will HS1 get the HS2 upgrade? If it did how quick will it get to Paris?

No, as the alignment isn’t fit for the higher speed, and there’s lots of tunnels / viaducts etc that are not built for the higher speed. And even if all that could be solved, given the distances involved, you’d be looking at a saving of 2 minutes at most.

 

[duesselmartin]

Germany is actually lowering speed targets with the new Munich to Berlin HSL set at 250kmh. Running at 300 is seen aus uneconomic. I would assume with the proposed lenght and stops in HS2, 400kmh will not be operational speed.

 

[hexagon789]

Germany is actually lowering speed targets with the new Munich to Berlin HSL set at 250kmh. Running at 300 is seen aus uneconomic. I would assume with the proposed lenght and stops in HS2, 400kmh will not be operational speed.

Indeed, 360 is the in-service speed.

 

[samuelmorris]

Indeed, 360 is the in-service speed.

Assuming it isn't lowered even further. With the proposed cutbacks (if it even goes ahead at all) and 'speed being lowered' I wonder if it'll end up at only 300 or even less.

 

[hexagon789]

Assuming it isn't lowered even further. With the proposed cutbacks (if it even goes ahead at all) and 'speed being lowered' I wonder if it'll end up at only 300 or even less.

320 maybe, surely no lower otherwise it'll hardly be worth it over the shorter distances.

 

[AM9]

320 maybe, surely no lower otherwise it'll hardly be worth it over the shorter distances.

Given the way that we run trains today on Victorian infrastructure at speeds that they couldn't even imagine when they were built, I suspect that the necessary enhancements would be made in due course provided there weren't any bends too tight for those speeds. If it was deemed important ehough to raise the speed, even with technically too small a curve radius, technology such as tilt together with more aggressive super-elevation could still be retro-fitted to the route.

 

[hexagon789]

Given the way that we run trains today on Victorian infrastructure at speeds that they couldn't even imagine when they were built, I suspect that the necessary enhancements would be made in due course provided there weren't any bends too tight for those speeds. If it was deemed important ehough to raise the speed, even with technically too small a curve radius, technology such as tilt together with more aggressive super-elevation could still be retro-fitted to the route.

I think absolute maximum, and that's only with significant re-engineering, on the classic network is probably about 155mph/250km/h.

Any faster and I think you really need an entirely new, segregated line. Even at just 155, on the congested WCML or ECML the difference in speeds between InterCity and Suburban trains would eat into capacity I think.

 

[Starmill]

SNCF seem to have decided that, drawing on their decades of experience and recent research and tests, 320km/h is the optimal speed for the journey lengths they're undertaking, when considering the cost of energy and maintenance against the revenues from faster journey times.

HS2 services will generally be on shorter journeys than long-distance TGVs currently make. I would suggest that aiming for a maximum commercial speed of more than 320 km/h was probably always unnecessary. The likelihood of the 360 target being cut seems fairly high to me.

I think a speed of lower than the existing 300km/h would be disappointing, though.

The Germans have decided that it's more efficient to build cheaper infrastructure on many routes, and crucially now with the ICE4 a cheaper train, that caps out at 250km/h, and accept that journey times will not be as competitive against the airlines as they are in France or Japan. This seems to work for them though, as they can sell themselves on comfort, environmental credentials and the new bargain Super Sparpreis fares. In this country, long-distance rail franchises do not seem even slightly interested in attracting passengers based on any of those 3 points, at least to me.

 

[Mikey C]

As the Javelins only go at 140mph (225 kmh) would Eurostars be able to go much faster without them getting in the way?

 

[cossie4i]

As the Javelins only go at 140mph (225 kmh) would Eurostars be able to go much faster without them getting in the way?

A Javelin will out accelerate a Eurostar, well the old ones not sure about the new ones.
The distance is so short between St Pancras and Ashford it doesn't make a lot of difference.
If I remember correctly Eurostar's only travel at 230 km/h from St Pancras to Ebbsfleet anyway.