Class 717 speed up-rating (85 to 100mph)

[choochoochoo]

Any idea why they'd bother going through the effort/expense of up-rating the speed of a 717 ?

99.99% of the time they run on slow lines where linespeed is below their current max speed.

The times when they do go on the fast are rare, and is an extra 15mph really worth it for those times. Especially as things are pretty disrupted if they are using the fast, or they are running empty.

Could it be Siemens are paying for it because they may have another potential operator elsewhere who would like them to operate at 100mph, and they can use GNs stock as test rigs.

I can't imagine GN planning on using them as 12 cars on what are (or were pre-pandemic) the busy outer commuter routes ?

 

[superalbs]

I didn't know they were? Where did you hear this?

 

[choochoochoo]

Let's just say it's insider information, but it's obviously not a secret as it's plastered on an ops notice case.

 

[43096]

Could it be Siemens are paying for it because they may have another potential operator elsewhere who would like them to operate at 100mph, and they can use GNs stock as test rigs.

Why would they? They can already demonstrate the 100mph Desiro City with the Class 700s.

 

[Ianno87]

Could be case like the 350s was - a relatively cheap software / pantograph change that gives extra capability. So why not?

 

[Energy]

Maybe fleet cominality with the 700s?

 

[choochoochoo]

Why would they? They can already demonstrate the 100mph Desiro City with the Class 700s.

Could be case like the 350s was - a relatively cheap software / pantograph change that gives extra capability. So why not?

Well they're still having to test them and replace certain equipment for the faster running. So there is expense and effort.

Cheap software ? There are functions GTR would like to bring over from 717 to 700 and the only possible reason it hasn't been done has to be cost.

 

[Wyrleybart]

I have no idea but as "43096" states, they are a variant of the "City" platform so I would expect very similar or identical kit under the floorboards. But why would they build in complications for the time when they slow lines are closed and the 717s have to run on the fast lines.

Unless they units are physically geared for better low speed acceleration and compromised maximum speed compared to the 700s.

 

[choochoochoo]

Don't know what's under the boards, but one piece of kit they're looking to change is the AWS horn. It may not be loud enough above 85mph.

I still can't work out why bother going to the effort.

 

[hexagon789]

Any idea why they'd bother going through the effort/expense of up-rating the speed of a 717 ?

99.99% of the time they run on slow lines where linespeed is below their current max speed.

The times when they do go on the fast are rare, and is an extra 15mph really worth it for those times. Especially as things are pretty disrupted if they are using the fast, or they are running empty.

Could it be Siemens are paying for it because they may have another potential operator elsewhere who would like them to operate at 100mph, and they can use GNs stock as test rigs.

I can't imagine GN planning on using them as 12 cars on what are (or were pre-pandemic) the busy outer commuter routes ?

Perhaps it's like the 444s? SWT first obtained approval to run them in passenger carrying service at 85mph, this apparently allowed them to enter service quicker than if approval for full 100mph running was obtained first.

After they had entered passenger service, permission to run at 100mph was then sought.

So, could the original reason be to get them in traffic quicker?

 

[choochoochoo]

Perhaps it's like the 444s? SWT first obtained approval to run them in passenger carrying service at 85mph, this apparently allowed them to enter service quicker than if approval for full 100mph running was obtained first.

After they had entered passenger service, permission to run at 100mph was then sought.

So, could the original reason be to get them in traffic quicker?

quite possibly, but why now go to the lengths to get them to 100mph when it's hardly going to be needed.

I dont know about 444s normal running, but do they get the chance to get to 100mph during normal service.

 

[hexagon789]

I dont know about 444s normal running, but do they get the chance to get to 100mph during normal service.

Yes, as did the 442s before them

 

[choochoochoo]

See, 717s would never get to 100mph in any of their current diagrams, so seems a bit pointless to up-rate them now.

Although maybe it's so that should the infrastructure ever improve so that the slows lines have a higher line speed, they can take advantage of it. I can't see that happening on the ECML though. Would be very useful on Hertford Loop between Gordon Hill and Stevenage.

 

[hexagon789]

See, 717s would never get to 100mph in any of their current diagrams, so seems a bit pointless to up-rate them now.

Although maybe it's so that should the infrastructure ever improve so that the slows lines have a higher line speed, they can take advantage of it. I can't see that happening on the ECML though. Would be very useful on Hertford Loop between Gordon Hill and Stevenage.

I see it as 'future-proofing', aren't they are designed for 100mph - as in the base design family? If so it makes sense to have them passed to run at this speed even if they don't current attain it.

(Though the power figures look a bit suspect, only 1,610hp for 204 tonnes?)

 

[apinnard]

Yes, as did the 442s before them

With a downhill gradient, a trailing wind and no motors cut out.

 

[hexagon789]

With a downhill gradient, a trailing wind and no motors cut out.

While I'll agree they were sluggish at higher speeds, they should be capable of 100mph readily enough given they had the same motors as the 4REPs they replaced and those could manage 100+ with two 4TCs in tow!

 

[apinnard]

While I'll agree they were sluggish at higher speeds, they should be capable of 100mph readily enough given they had the same motors as the 4REPs they replaced and those could manage 100+ with two 4TCs in tow!

The motors from one REP unit went into 2x motor cars for class 442. Theoretically a 2x 5 car 442 has the same installed power as 1x 4REP. Whether or not that makes a difference at the rail, I am sure a driver can tell us. They seem to be slow in comparison to more modern stuff.

 

[hexagon789]

The motors from one REP unit went into 2x motor cars for class 442. Theoretically a 2x 5 car 442 has the same installed power as 1x 4REP. Whether or not that makes a difference at the rail, I am sure a driver can tell us. They seem to be slow in comparison to more modern stuff.

I admit my previous assertion was based on a guess that a ten-car 442's total weight was less than that of a 4REP+4TC+4TC and thus the power-to-weight ratio would get higher.

Using the weights obtained from the diagram books I calculate:

10 (or 5)-car 442: 7.93hp per tonne
4REP+4TC+4TC: 7.26hp per tonne

So a 442 should perform a bit better.

 

[AverageTD]

I was taking a 717 once between Finsbury Park and New Barnet, for reasons unknown we were sent on to the fasts and ran non-stop between the 2 stations. 100mph may have been useful then...

 

[choochoochoo]

I was taking a 717 once between Finsbury Park and New Barnet, for reasons unknown we were sent on to the fasts and ran non-stop between the 2 stations. 100mph may have been useful then...

probably more useful to the fast train stuck behind it

 

[AM9]

I admit my previous assertion was based on a guess that a ten-car 442's total weight was less than that of a 4REP+4TC+4TC and thus the power-to-weight ratio would get higher.

Using the weights obtained from the diagram books I calculate:

10 (or 5)-car 442: 7.93hp per tonne
4REP+4TC+4TC: 7.26hp per tonne

So a 442 should perform a bit better.

I suspect that the 442 with some streamlining and smoother outlines has less wind resistance than the slab front and spiky exterior of the 432/438 combo. The 442 would have a greater holtel load with the a/c running though.

I see it as 'future-proofing', aren't they are designed for 100mph - as in the base design family? If so it makes sense to have them passed to run at this speed even if they don't current attain it.

(Though the power figures look a bit suspect, only 1,610hp for 204 tonnes?)

I think that the 1200kW per unit figure is suspect as well. That's the same as the 707s which weigh 39tonnes less, yet they are set for 100mph max. Maybe that is the 717s derated figure for when they are running on 750VDC. I can see no reason why they would be any different to half of a 12-car 700, (which is in itself configured as two 6-car sub-units). That would suggest about 2500kW per 717 then.

 

[hexagon789]

I suspect that the 442 with some streamlining and smoother outlines has less wind resistance than the slab front and spiky exterior of the 432/438 combo. The 442 would have a greater holtel load with the a/c running though.

That is true but isn't the hotel load taken straight from the third rail suplly and not as with diesels from the engine - ie it doesn't use up traction power

I think that the 1200kW per unit figure is suspect as well. That's the same as the 707s which weigh 39tonnes less, yet they are set for 100mph max. Maybe that is the 717s derated figure for when they are running on 750VDC. I can see no reason why they would be any different to half of a 12-car 700, (which is in itself configured as two 6-car sub-units). That would suggest about 2500kW per 717 then.

I seems way too low, it would give them about the same power-to-weight as the 313s and these are supposed to be 85mph capable at least. Do the 717s have two motor cars? If so my thinking was it could be the figure for ONE motor car.

That would make more sense and give them a much more sprightly power-to-weight ratio more in keeping with the ratios of modern trains.

 

[AM9]

That is true but isn't the hotel load taken straight from the third rail suplly and not as with diesels from the engine - ie it doesn't use up traction power

Yes of course, I was thinking in ac terms.

I seems way too low, it would give them about the same power-to-weight as the 313s and these are supposed to be 85mph capable at least. Do the 717s have two motor cars? If so my thinking was it could be the figure for ONE motor car.

That would make more sense and give them a much more sprightly power-to-weight ratio more in keeping with the ratios of modern trains.

Assuming that was the case, then a 6-car unit with 2400kW wouild seem a good spin-off of the class 700 design and might make a good match for updating SE services alonside the 700s running to Rainham, Sevenoaks et al. Of course their maximum power would be lower on DC and there might be some platform length issues (i.e. many have been upgraded to accommodate 10-car trains). Their high capacity and performance with a degree of training and maintenance commonality with the largest fleet of the new train designs (class 700s) might make them a good fit.

 

[apinnard]

That is true but isn't the hotel load taken straight from the third rail suplly and not as with diesels from the engine - ie it doesn't use up traction power

I assumed, probably incorrectly, that the 442 have/had motor alternators that converted the dc from the batteries into ac for hotel supply. These probably being replaced with inverters as part of their upgrade.

That said, there was one (2416 I believe) that had Liebherr hvac kit fitted in the mid 2000’s that was fed directly from the third rail. I believe it was a disaster, and the reason that particular unit usually carted around crates of bottled water in its final days with SWT, so the punters could cool themselves down.

Anyway, this is way off topic, so back to the 717’s...

 

[hwl]

I assumed, probably incorrectly, that the 442 have/had motor alternators that converted the dc from the batteries into ac for hotel supply. These probably being replaced with inverters as part of their upgrade.

That said, there was one (2416 I believe) that had Liebherr hvac kit fitted in the mid 2000’s that was fed directly from the third rail. I believe it was a disaster, and the reason that particular unit usually carted around crates of bottled water in its final days with SWT, so the punters could cool themselves down.

Anyway, this is way off topic, so back to the 717’s...

Didn't the 442s as built have inverters but these were just before EMC regs era and these are now having to be replaced as part of the solution to rectify the disco signals problem?

 

[Bald Rick]

Complete guess - could it be that with the downturn in commuter traffic, some of the 717s are going to be ‘spare’, and could be deployed on other GN services where the 100mph capability would be useful? Thus releasing other stock for the scrap heap (and not necessarily from the GN).

 

[Ianno87]

Complete guess - could it be that with the downturn in commuter traffic, some of the 717s are going to be ‘spare’, and could be deployed on other GN services where the 100mph capability would be useful? Thus releasing other stock for the scrap heap (and not necessarily from the GN).

The fleet is sized for a full Moorgate peak service, which may credibly never be needed again.

Meanwhile, 2 x 6-cars could enable taking the 365s for the peak Peterborough/Baldock services off-lease...

 

[43096]

Meanwhile, 2 x 6-cars could enable taking the 365s for the peak Peterborough/Baldock services off-lease...

As owners of the 365 fleet, why would DfT want to shoot themselves in the foot by taking 365s off lease. They should be looking to get them all back in use!

 

[Energy]

As owners of the 365 fleet, why would DfT want to shoot themselves in the foot by taking 365s off lease. They should be looking to get them all back in use!

The DfT got them for free so they wouldn't be losing money just not gaining any.

 

[43096]

The DfT got them for free so they wouldn't be losing money just not gaining any.

They didn't get them for free, and they're also paying out for storage on the units that are currently off lease.