Where can Electrostars/Desiros actually reach 100mph

[bramling]

Yes that’s another loose end not very well documented. I’ve seen an enhancements report written Mar 2019 written as though that was at “will be completed” status, but it looks to me as though the project info, ie “Wessex DC regeneration” was unchanged for quite a number of reports.

Probably need someone on the inside of NR’s electrification teams to give the definite answer on this one.

 

[dtin]

377/2s will hit (signals permitting) 100mph between Harrow and Watford Junction. Usually getting there just before Carpenders Park. On the Up if the Bushey stopper is out the way then you’ll hit the ton at Headstone Lane.

However. From May the Watfords & Hemels become 377/5 and they won’t make the 100mph before you have to slow down for the next PSR.

When Southern ran as far as Milton Keynes Central would the 377 reach 100 mph on that section?

== Doublepost prevention - post automatically merged: 9 Apr 2023 ==

The Diesel Desiro (185) frequently did 100mph at various locations between Wigan and Glasgow/Edinburgh, and on the ECML to Newcastle.

Now they only place a 185 will hit 100mph is between Church Fenton and York, and on the ECML on the way to Saltburn.

The 350/4, once upgraded, could run at 110mph at various locations between Wigan and Glasgow/Edinburgh.

With the diesel transpenine desiros I know there were a number of locations where they could reach max speed on the WCML and ECML.

 

[TurboMan]

Fastest Electrostar will be on the Great Western with 110mph running on the Newbury & Bristol/Cardiff 387s

And HEx.

 

[Kite159]

And HEx.

Do they hit 110mph between Paddington & Airport Junction?

 

[800301]

Do they hit 110mph between Paddington & Airport Junction?

It’s 125 from just after Acton Main Line so yes they would be hitting 110

 

[Ken H]

I know 25kv ac isnt always at that voltage at times when the national grid is under pressure, and electric trains will run at lower voltages with no ill effects. Or the older ones did - dont know if newer trains will run at a reduced voltage. What would a Cl 390 make of 13Kv, for example.

But does a reduction in grid voltage affect 3rd rail DC voltages? And what does that do to train performance - I imagine it is detrimental.

 

[zwk500]

But does a reduction in grid voltage affect 3rd rail DC voltages? And what does that do to train performance - I imagine it is detrimental.

Power equals Voltage x Amps, (PIV triangle), so yes if the track voltage drops trains will get less power (as the amps won't raise to compensate). The grid voltage can fluctuate slightly without the actual voltage going beyond the limits because it's transformed at the supply points/substations, but AIUI if the voltage goes beyond the designed limits the sectoins start tripping out to prevent serious damage.

 

[Southern Dvr]

I doubt this is true. What is your source for this?

Typo. I didn’t mean 377/5. I meant 5-car 377/7. Apologies folks. Failed to proof read.

 

[hexagon789]

I know 25kv ac isnt always at that voltage at times when the national grid is under pressure, and electric trains will run at lower voltages with no ill effects. Or the older ones did - dont know if newer trains will run at a reduced voltage. What would a Cl 390 make of 13Kv, for example.

But does a reduction in grid voltage affect 3rd rail DC voltages? And what does that do to train performance - I imagine it is detrimental.

BR, when timetabling the WCML, used to assume a voltage of 22.5kV. The 1974 timetable was based on that premise, as well as 87s being on 3 traction motors (hence why the timings and loads on passenger services for 87s and 86/1s was the same as for 86/2s despite the almost 1,000hp difference of the latter.

Similarly, the Southern Region assumed line voltage was (IIRC) ~90% of nominal for timetabling.

 

[alf]

Apparently you get better quality electricity on Sundays & so greater speed.

Less demand on grid so 50 cycles per sec and ac at full voltage.
(when the grid is stretched at weekday peak hours Grid controllers allow cycles per sec to drop below 50 to stop voltage drop which can have calamitous consequences)

Also there are fewer electric trains than weekdays so less power to share with other trains in section.
Thus more likely to get full 750dc & 25kv & max performance.

I was told this by railway electric engineer years ago. It seems likely to be true.

 

[Jamesrob637]

Evening departures from Paddington are fast to Maidenhead or Reading. They'll do some pretty good speed.

 

[D365]

Less demand on grid so 50 cycles per sec and ac at full voltage.
(when the grid is stretched at weekday peak hours Grid controllers allow cycles per sec to drop below 50 to stop voltage drop which can have calamitous consequences)

OT, but presumably the frequency at weekends is set in order so that grid frequency averages out at 50Hz overall.

 

[Magdalia]

the Greater Anglia Electrostars which used to do the stansted express and West Anglian routes.

No 100 mph running there. Maximum was a few short sections at 90 mph.

 

[Davester50]

Is there 100 mph running to North Berwick for the 380s?

 

[notadriver]

All third rail powered EMUs are heavily restricted as to their maximum current draw when in multiple. The longer the formation the slower the train. This does not apply so much on AC overhead lines where this software restriction isn’t in place.

Desiro DC third rail are particularly hampered and take a full 90 seconds to reach 60 mph irrespective of whether they are a single 4 car 450 or a heavier 5 car 444. They are even slower in multiple. I believe they are set on the lower amps setting.

Electrostars however can take more advantage in 4 car mode but are significantly slower in multiple. In 4 car mode 60 mph can be reached in 70 seconds.

== Doublepost prevention - post automatically merged: 10 Apr 2023 ==

I remember the speed run from Dover to Victoria carried out just before the CEPs finished. A full-on run towards Tonbridge from the Ashford direction, followed by very heavy and last-minute braking as the train passed through Tonbridge on the fast lines. A memorable experience, though one which was probably fairly typical during the boat train years.

CEPs / VEPs etc had a level balancing speed of around 80 mph. 90 mph was only really possible with a downhill stretch. Only contemporary units such as modified Greyhound sets (421s with additional field weakening) and higher geared 4REPS could attain and sustain their 90 mph maximum even with 8TC coaches in tow. A 4REP+ 8TC was quicker than a 12 VEP/ CEP formation despite a nominally similar total output of 3200/3000 hp (even that’s the one hour rating). 4REPS * 8TC could climb from Eastleigh to Basingstoke at 80 mph a speed which other slam door express EMUs could only exceed on level track.

 

[JN114]

Do they hit 110mph between Paddington & Airport Junction?

Easily

 

[notadriver]

The Diesel Desiro (185) frequently did 100mph at various locations between Wigan and Glasgow/Edinburgh, and on the ECML to Newcastle.

Now they only place a 185 will hit 100mph is between Church Fenton and York, and on the ECML on the way to Saltburn.

The 350/4, once upgraded, could run at 110mph at various locations between Wigan and Glasgow/Edinburgh.

I think it’s very much a waste to have a diesel powered unit on the WCML going to Glasgow / Edinburgh as its electrified in its entirety.

185s still get plenty of 100 mph cruising between church Fenton and Thirsk where they are switched to slow lines as they call there. They are as quick as an electrostar on 3rd rail DC power and like Voyagers embarrass a third rail powered Desiro which are incredibly slow accelerating due to software limitations on power consumption. 185s will reach 100 mph quicker than the equivalent 180 departing York and far quicker than an HST set would. I’m not sure how healthy the 220s are these days - maybe someone could tell me ?

 

[Magdalia]

(when the grid is stretched at weekday peak hours Grid controllers allow cycles per sec to drop below 50 to stop voltage drop which can have calamitous consequences)

Allowing cycles per second to drop can also have calamitous consequences.

The multiple failures of class 700s on the ECML and MML on 9 August 2019 were attributed to this.

 

[zwk500]

Allowing cycles per second to drop can also have calamitous consequences.

The multiple failures of class 700s on the ECML and MML on 9 August 2019 were attributed to this.

Drop too far, yes. They do have a certain tolerance though.
The August 19 failure was a perfect storm caused by an incomplete software upgrade as well as the extremely rare event of 2 major generating units going offline in quick succession, IIRC.

 

[Ken H]

Allowing cycles per second to drop can also have calamitous consequences.

The multiple failures of class 700s on the ECML and MML on 9 August 2019 were attributed to this.

Gridwatch is a good site to watch the grid health in real time. Including frequency.

G. B. National Grid status

www.gridwatch.templar.co.uk

Link goes to graphical display of elelctric demand, frequency and generation output by type wtc.

 

[Bletchleyite]

350s go all the way up to 110 on the WCML, and on the fast lines they are smooth as silk at that speed, you can barely feel it moving.

 

[Flange Squeal]

A 4rep reached 105mph between farnborough and basingstoke on s test run on the Swml so i can imagine a 444/450 can

Even from a standing start at Farnborough, a Desiro going onto the Down Fast there can reach 100mph around Winchfield.

 

[dtin]

Is there 100 mph running to North Berwick for the 380s?

Not sure about the line speeds in Scotland as I live down south, but there may be 100 mph sections on the WCML from Edinburgh to Glasgow via Carstairs or between Glasgow Central and Lanark as they share these tracks with the fast trains to Glasgow.

 

[Jamesrob637]

350s go all the way up to 110 on the WCML, and on the fast lines they are smooth as silk at that speed, you can barely feel it moving.

Completely agree and they're a good cheaper option from Manchester to London via Crewe or Stoke-on-Trent

 

[Dhansak]

What is the speed limit along the Quarry Line section of the BML? I have been on 377-operated services which have come very close to 100mph (according to the GPS on my phone anyway).

 

[zwk500]

What is the speed limit along the Quarry Line section of the BML? I have been on 377-operated services which have come very close to 100mph (according to the HPS on my phone anyway).

Fasts/Quarry lines are 90 from South Croydon to southern end of Redhill tunnel, then 80 to London end of Earlswood.

 

[hexagon789]

Is there 100 mph running to North Berwick for the 380s?

Yes, in fact speeds of up to 125 are encountered before Drem Jcn. but on the North Berwicks I usually find 90-95 to be the maximum attained between stations depending on spacing. The Dunbars do make 100 and sustain it though, as they only stop at Musselburgh and then have the longer run out to Dunbar still on the ECML.

Not sure about the line speeds in Scotland as I live down south, but there may be 100 mph sections on the WCML from Edinburgh to Glasgow via Carstairs or between Glasgow Central and Lanark as they share these tracks with the fast trains to Glasgow.

The Edinburgh-Carstairs is 95 max, on the WCML proper there are a couple of 100 sections between Carstairs Yard and Carluke and a 105 section on the down near Shieldmuir.

== Doublepost prevention - post automatically merged: 11 Apr 2023 ==

What is the speed limit along the Quarry Line section of the BML? I have been on 377-operated services which have come very close to 100mph (according to the GPS on my phone anyway).

The BML is 90 max. There was previously a 100 section through Gatwick Airport for the 319-operated Connex 47-min Brighton Express services. Only the Brighton Express 319s were authorise to use it and it was removed some years ago; everything else then and everything since has been limited to 90mph.

 

[AM9]

Yes, in fact speeds of up to 125 are encountered before Drem Jcn. but on the North Berwicks I usually find 90-95 to be the maximum attained between stations depending on spacing. The Dunbars do make 100 and sustain it though, as they only stop at Musselburgh and then have the longer run out to Dunbar still on the ECML.


The Edinburgh-Carstairs is 95 max, on the WCML proper there are a couple of 100 sections between Carstairs Yard and Carluke and a 105 section on the down near Shieldmuir.

== Doublepost prevention - post automatically merged: 11 Apr 2023 ==


The BML is 90 max. There was previously a 100 section through Gatwick Airport for the 319-operated Connex 47-min Brighton Express services. Only the Brighton Express 319s were authorise to use it and it was removed some years ago; everything else then and everything since has been limited to 90mph.

Were those speed limits all for track issues or would the potential for overloading the 3rd rail supply in places be a consideration in setting a sub 100mph maximum for trains that were 100mph capable?

 

[PGAT]

Weren’t some sections of the BML 100 mph at some point?

 

[sk688]

What's the top speed that 350s reach on services out of Euston that are first stop Watford , or vice versa Watford-Euston non-stoppers ?