How did Class 360s get their speed uprated from 100mph to 110mph maximum?

[2192]

The advantage of different gearing on 75mph units (compared to 100mph ones) is that the acceleration is improved -- useful for suburban trains with frequent stops that seldom achieve top speed.

 

[AM9]

There would have been a handful of places on the fast lines on the MML too, but mainly only affecting the roughly 6 trains per day using them between Bedford and Luton, and still saving mere seconds, just as you say.

The Siemens Desiro Verve is offered (although not taken up by the UK), as a 125mph train using enhanced versions of the Desiro City's SF7000 bogies. Thus it would seem that a smaller speed increement from 100 to 110 might be a possibility if needed. The future of 125mph EMUs (class 397) seems to be with inside frame bogies so it is likely that if 'desired' (puns aside) the 700s could be upgraded especially if they were ever to see service beyond Bedford. Their single-unit fixed configurations meaning that multiple pantograph performance does not get compromised when non-standard consists are deployed by depots.

 

[edwin_m]

The advantage of different gearing on 75mph units (compared to 100mph ones) is that the acceleration is improved -- useful for suburban trains with frequent stops that seldom achieve top speed.

Much less so with AC motors - they are more able to sustain acceleration at higher speeds so there is less need to fine-tune the gearing for the best combination of speed and acceleration for a particular duty.

The Siemens Desiro Verve is offered (although not taken up by the UK), as a 125mph train using enhanced versions of the Desiro City's SF7000 bogies. Thus it would seem that a smaller speed increement from 100 to 110 might be a possibility if needed. The future of 125mph EMUs (class 397) seems to be with inside frame bogies so it is likely that if 'desired' (puns aside) the 700s could be upgraded especially if they were ever to see service beyond Bedford. Their single-unit fixed configurations meaning that multiple pantograph performance does not get compromised when non-standard consists are deployed by depots.

However, the pantograph spacing may be too close to allow operation at higher speeds. There are also extra crashworthiness regulations that apply when the top speed is greater.

 

[Domh245]

However, the pantograph spacing may be too close to allow operation at higher speeds

The smallest spacing on a 700 is a tad over 80m on an 8 car (inside ends of vehicles 2 & 7), so it'd be little different to a pair of 360s

 

[D6975]

The smallest spacing on a 700 is a tad over 80m on an 8 car (inside ends of vehicles 2 & 7), so it'd be little different to a pair of 360s

But a 700 is a single unit and normally runs with only one pan raised.

 

[Domh245]

But a 700 is a single unit and normally runs with only one pan raised.

They're effectively 2 units masquerading as one (see also 345s, 701/0s), and run with both pantographs raised

eg this picture (not mine): https://flic.kr/p/2j7cECs

 

[43096]

But a 700 is a single unit and normally runs with only one pan raised.

You might want to revise that statement.

As an example: https://flickr.com/photos/mrc31176/...2mWvXGJ-2kpXrUx-2mxAztQ-2iUcKLr-Nd4ej5-ADxmVN

 

[Fincra5]

Thats not correct... 700s are basically two units permanently coupled together to form 1 Unit. Each Pan powers 4 or 6 coaches (RLU or FLU) respectively.

There is no BUS line between the two units. So if one half has a pan down, half is effectively being dragged.

But a 700 is a single unit and normally runs with only one pan raised.

 

[Ken H]

Thats not correct... 700s are basically two units permanently coupled together to form 1 Unit. Each Pan powers 4 or 6 coaches (RLU or FLU) respectively.

There is no BUS line between the two units. So if one half has a pan down, half is effectively being dragged.

I am confused.
I read a fair bit about how LT trains worked a (long) while back. The MU system was necessary because the Board of Trade did not favour power lines running down trains. So each set of equipment needed its own set of shoegear. This was early 20th century when Yerkes was building his tubes.

But we now see Pendolinos with high voltage power lines running the length of trains. And Fincra5 says 1 pan powers several coaches on the 700's

Are the rules different for Tubes, or have the rules been relaxed?

 

[Snow1964]

The Siemens Desiro Verve is offered (although not taken up by the UK), as a 125mph train using enhanced versions of the Desiro City's SF7000 bogies. Thus it would seem that a smaller speed increement from 100 to 110 might be a possibility if needed. The future of 125mph EMUs (class 397) seems to be with inside frame bogies so it is likely that if 'desired' (puns aside) the 700s could be upgraded especially if they were ever to see service beyond Bedford. Their single-unit fixed configurations meaning that multiple pantograph performance does not get compromised when non-standard consists are deployed by depots.

Siemens have designed it for 200km/h (124mph). It can then be down spec’d for reduced maximum speeds. It is a saving on development costs and standardisation of main parts (which reduces tooling and manufacturing costs), and of course simplifies spare parts if a depot has lots of them but in 2 configurations.

In the UK there are additional crash worthiness requirements for operating at over 110mph. We don’t really have express EMUs that would do sustained running over 110mph anyway (the intercity type 800 series are on those services, which are designed for 125-140mph). However it should be noted that the 100mph and 110mph max speeds without extra crash protection seem to have been set based on what was running at the time, rather than a specific speed being chosen following tests.

 

[westcoaster]

another question i was on a 700 and it has a stop speed of 100mph in the cab it says 100mph max speed but it was doing and holding 104 and 107mph(on my phone between finsbury park and stevenage) ive seen this in yt vids and on my spedometer they can do over 100mph? seen this with the 444 700 and other trains that do 100mph

Not possible I'm afraid.
700's have a speed protection feature built into them, power is automatically cut (102mph and a fault message appears) and not able to be re applied.

 

[AM9]

Siemens have designed it for 200km/h (124mph). It can then be down spec’d for reduced maximum speeds. It is a saving on development costs and standardisation of main parts (which reduces tooling and manufacturing costs), and of course simplifies spare parts if a depot has lots of them but in 2 configurations.

In the UK there are additional crash worthiness requirements for operating at over 110mph. We don’t really have express EMUs that would do sustained running over 110mph anyway (the intercity type 800 series are on those services, which are designed for 125-140mph). However it should be noted that the 100mph and 110mph max speeds without extra crash protection seem to have been set based on what was running at the time, rather than a specific speed being chosen following tests.

So it would seem that if there was a case for running the 700s in amongst existing higher speed services without losing paths, (e.g. ECML or MML fasts), that they could be adjusted relatively cheaply. That would put them in a similar position to the Desiro UK and class 387 Electrostars.
The class 397s are supposed to be true 125mph trains, - but of course they are CAF designed!

Not possible I'm afraid.
700's have a speed protection feature built into them, power is automatically cut (102mph and a fault message appears) and not able to be re applied.

That is a limitation set at delivery specific to their current role, and any modification to clear them for 110mph would include adjusting any speed protection feature as appropriate for the new maximum operational speed (112mph?). Personally, I think it would be interesting to travel in them at that speed, - they ride pretty well at 100mph - often over not particularly good track.

 

[Ken H]

Not possible I'm afraid.
700's have a speed protection feature built into them, power is automatically cut (102mph and a fault message appears) and not able to be re applied.

Is the input to the speed protection the same as the speedo? Is the speedo and speed protection regularly calibrated, i.e after wheel turning?

 

[edwin_m]

I am confused.
I read a fair bit about how LT trains worked a (long) while back. The MU system was necessary because the Board of Trade did not favour power lines running down trains. So each set of equipment needed its own set of shoegear. This was early 20th century when Yerkes was building his tubes.

But we now see Pendolinos with high voltage power lines running the length of trains. And Fincra5 says 1 pan powers several coaches on the 700's

Are the rules different for Tubes, or have the rules been relaxed?

The Underground have never had DC bus lines down the train as far as I'm aware, but the Southern third rail units had and have them. Possibly something to do with the worse consequences of arcing and fire when in a tunnel?

I think one of the reasons for the APT having both power cars in the middle (with no through passenger access so needing two buffets etc) was unwillingness to run an AC bus down the roof at the time. But TGVs and Pendlolinos have them so there's clearly no objection in principle to them today, even on a tilting train where the linkage must presumably cope with a failure where two cars tilt in opposite directions.

 

[Fincra5]

The Underground have never had DC bus lines down the train as far as I'm aware, but the Southern third rail units had and have them. Possibly something to do with the worse consequences of arcing and fire when in a tunnel?

I think one of the reasons for the APT having both power cars in the middle (with no through passenger access so needing two buffets etc) was unwillingness to run an AC bus down the roof at the time. But TGVs and Pendlolinos have them so there's clearly no objection in principle to them today, even on a tilting train where the linkage must presumably cope with a failure where two cars tilt in opposite directions.

Incidentally 313s didn't have a busline until modified to do so!

 

[edwin_m]

Incidentally 313s didn't have a busline until modified to do so!

They must have had something, because the pantograph and transformer were on the middle car and they needed to feed power to the motors on the end ones. But perhaps that was disconnected when in DC mode, or each motor car had a separate rectifier so there was no route for DC from one to the other? That would make sense considering the Moorgate line was previously part of the Underground and very similar in most respects, so whatever safety concerns applied to Tube trains would probably apply there too.

 

[hexagon789]

They must have had something, because the pantograph and transformer were on the middle car and they needed to feed power to the motors on the end ones. But perhaps that was disconnected when in DC mode, or each motor car had a separate rectifier so there was no route for DC from one to the other? That would make sense considering the Moorgate line was previously part of the Underground and very similar in most respects, so whatever safety concerns applied to Tube trains would probably apply there too.

On DC each 313 motor coach draws its own 750V supply separately.

 

[edwin_m]

On DC each 313 motor coach draws its own 750V supply separately.

Yes, but what happens in AC mode?

 

[Ken H]

Yes, but what happens in AC mode?

I would assume the ac kit feeds the DC via jumpers. But when in DC mode the jumpers are not live and the 2 DC equipments are not connected electrically.

 

[hexagon789]

Yes, but what happens in AC mode?

25kV obviously collected by the pantograph, presumably there's a transformer and rectifier to convert to 750V for the motors, so there must be a bus line for AC working? I can't see how else you get the power from the centre pantograph trailer to the motor cars.

 

[edwin_m]

25kV obviously collected by the pantograph, presumably there's a transformer and rectifier to convert to 750V for the motors, so there must be a bus line for AC working? I can't see how else you get the power from the centre pantograph trailer to the motor cars.

Exactly. But if that bus connected simply from a single rectifier output to both sets of DC control gear it would also bridge the DC shoes. Electrically separate rectifiers and connecting cables for each car (either in the end cars or both in the middle one) would block any DC going from end to end, or there could be contactors that disconnected the DC bus when in DC supply mode.

 

[hexagon789]

Exactly. But if that bus connected simply from a single rectifier output to both sets of DC control gear it would also bridge the DC shoes. Electrically separate rectifiers and connecting cables for each car (either in the end cars or both in the middle one) would block any DC going from end to end, or there could be contactors that disconnected the DC bus when in DC supply mode.

Presumably selection of DC mode somehow isolates the supply bus. I can't find specifics other than to say that regulations for underground working on DC meant it was necessary for separate 750V DC power collection on each power car but nothing to say precisely how that was accomplished other than that the power cars have collection shoes on both bogies rather than just the outer ones.

 

[507020]

Post #6,177 on the Northern 769 thread states that

The Class 313/2s are dc only units. As built they were not allowed to have a dc bus active in the underground tunnels so each motor coach had its separate dc pick up. On ac the pantograph and transformer fed both motor coaches. On the West Coastway lines there are loads of wide level crossings at the end of platform ramps so there was a real risk of the units becoming gapped and they wouldn't have been able to keep to the timetable pulling away on half power so the 313/2 conversion disconnected the ac equipment and used the previous cables from the dc side of the transformer to the motor coaches, linked together to provide a dc bus so either set of shoes can power all the traction motors.

So it appears that there were always 750V DC cables in use in AC mode, but never a through bus line between the shoes on each end car when in DC mode, but the Southern units have now rectified this, at the expense of them no longer being able to operate on AC.

 

[D365]

From a quick flick through the (now extinct) Class 313/0 electrical schematics, it looks like the traction changeover system on the 313s was used to connect the 750V DC bus on overhead, and disconnect on third rail. Presumably, on the Coastway 313/2s, the electrical switching was bypassed to make it a permanent bus line on third rail.

 

[aleggatta]

From a quick flick through the (now extinct) Class 313/0 electrical schematics, it looks like the traction changeover system on the 313s was used to connect the 750V DC bus on overhead, and disconnect on third rail. Presumably, on the Coastway 313/2s, the electrical switching was bypassed to make it a permanent bus line on third rail.

I’d be interested to see the original schematics, only having access to some of the 313/2 documents leaves me with an itch as to how the AC equipment worked. But as far as I know they literally just linked the two feeds from the rectifier to create the bus line, linking in a couple of DC shore supply connectors at the vehicle ends with the inter car dc link. There were other mods to add a DC aux supply socket also.

 

[XAM2175]

I think one of the reasons for the APT having both power cars in the middle (with no through passenger access so needing two buffets etc) was unwillingness to run an AC bus down the roof at the time. But TGVs and Pendlolinos have them so there's clearly no objection in principle to them today, even on a tilting train where the linkage must presumably cope with a failure where two cars tilt in opposite directions.

Correct. It's a bit amusing recalling that fact when seeing how conspicuous the bus line is on a 397.

 

[edwin_m]

From a quick flick through the (now extinct) Class 313/0 electrical schematics, it looks like the traction changeover system on the 313s was used to connect the 750V DC bus on overhead, and disconnect on third rail. Presumably, on the Coastway 313/2s, the electrical switching was bypassed to make it a permanent bus line on third rail.

Thinking about it a bit more, they'd have to disconnect the DC bus somewhere, otherwise the shoegear would be live in AC mode. I doubt this would have been acceptable even back in the 70s - people working on the DC railway expect live shoegear even if it's not sitting on a third rail, but those elsewhere probably wouldn't.

 

[Ken H]

Thinking about it a bit more, they'd have to disconnect the DC bus somewhere, otherwise the shoegear would be live in AC mode. I doubt this would have been acceptable even back in the 70s - people working on the DC railway expect live shoegear even if it's not sitting on a third rail, but those elsewhere probably wouldn't.

Is shoegear out of gague in non DC areas. Isnt that why cl73 had retractable shoegear? So how did that work north of Drayton Pk?

 

[D365]

Is shoegear out of gague in non DC areas. Isnt that why cl73 had retractable shoegear? So how did that work north of Drayton Pk?

Class 313 were cleared to Royston and St Neots.

Worth pointing out also that Class 700 doesn’t have retractable shoegear either.

 

[507020]

Is shoegear out of gague in non DC areas. Isnt that why cl73 had retractable shoegear? So how did that work north of Drayton Pk?

It may be. There is a slightly different W6a gauge for DC areas than the plain W6 elsewhere.