Question regarding speed limits and combinations of stock with different speed limitations

[61653 HTAFC]

In the book Train Doctor (Roger Senior) pg 155 there is a story edited a little

That's the sort of thing that inspired my original question. I remember hearing talk of drivers in 158s forgetting that they had a 142 on the back, and hitting 90mph. One would hope for the driver's sake that there are ways of preventing such things, especially now that OTMR is in place.

 

[hexagon789]

That's the sort of thing that inspired my original question. I remember hearing talk of drivers in 158s forgetting that they had a 142 on the back, and hitting 90mph. One would hope for the driver's sake that there are ways of preventing such things, especially now that OTMR is in place.

Yes, I've heard a similar tale of a 158/142 combo, possibly even the same one.

 

[scotraildriver]

That's the sort of thing that inspired my original question. I remember hearing talk of drivers in 158s forgetting that they had a 142 on the back, and hitting 90mph. One would hope for the driver's sake that there are ways of preventing such things, especially now that OTMR is in place.

Nope. We can have 170/156 combo and nothing to stop you dragging the 156 to 100!

 

[hexagon789]

Nope. We can have 170/156 combo and nothing to stop you dragging the 156 to 100!

Or even 103, seeing as that is where a 170's limited kicks in!

 

[61653 HTAFC]

Nope. We can have 170/156 combo and nothing to stop you dragging the 156 to 100!

Do some of you have your own reminders? Even something simple like a post-it note stuck to the desk would help, I imagine!

 

[hexagon789]

Do some of you have your own reminders? Even something simple like a post-it note stuck to the desk would help, I imagine!

I think some TOCs have little reminder plates or something.

 

[route:oxford]

Nope. We can have 170/156 combo and nothing to stop you dragging the 156 to 100!

Other than the 170 itself being barely powerful enough to get to 100mph

The 156s were temporarily allowed to operate at 90mph on Scotrail during the 158 emergency withdrawal weren't they?

 

[gingertom]

Other than the 170 itself being barely powerful enough to get to 100mph

The 156s were temporarily allowed to operate at 90mph on Scotrail during the 158 emergency withdrawal weren't they?

IIRC there was a dispensation to run 156s at 80mph whilst they dealt with the 158s' interaction with signals.

 

[hexagon789]

IIRC there was a dispensation to run 156s at 80mph whilst they dealt with the 158s' interaction with signals.

Interesting, I've never heard of that. I know several drivers got them up to 85 and beyond in the early days, but I didn't know a temporary dispensation had been granted.

 

[Wilts Wanderer]

There was a greater tolerance of overspeed on BR though, I think it may even have been official policy to permit 5mph over the posted limit when a train was running a certain amount late.

 

[hexagon789]

There was a greater tolerance of overspeed on BR though, I think it may even have been official policy to permit 5mph over the posted limit when a train was running a certain amount late.

I know there was a greater tolerance of overspeed, bit of don't think there was an official overspeed when running late policy. Though I seem to recall the rulebooks used to have a bit which read: "driver when running late, should endeavour wherever possible, to make up lost time with due regard to all permanent speed restrictions" or something like that. I suppose that could be construed as allowing linespeed to be exceeded but not Permanent Speed Restrictions.

 

[Wilts Wanderer]

That quote is written on every BR working timetable I’ve ever seen.

 

[hexagon789]

That quote is written on every BR working timetable I’ve ever seen.

Couldn't remember if it was the rule book or working timetable, I suppose it could be both.

 

[randyrippley]

Other than the 170 itself being barely powerful enough to get to 100mph

The 156s were temporarily allowed to operate at 90mph on Scotrail during the 158 emergency withdrawal weren't they?

No they weren't

 

[hexagon789]

No they weren't

I didn't think so.

 

[themiller]

I seem to remember that, not long after they were introduced, one unit exceeded 90mph on a test run somewhere between Leeds and York. It was in the railway press at the time but I don't think that it was on a public service. Of course, I could be mistaken and the unit I remember was a 155 but I don't think so as the 155s were sidelined for months because of a problem with the doors(?). This means that the 156s are (or were) capable of 90 but that they may now be limited by instruction rather than capability as I've been on one on a Barrow to Preston service which seemed to fly once on the WCML although this is very subjective and I only roughly timed a couple of quarter miles.

 

[hexagon789]

I seem to remember that, not long after they were introduced, one unit exceeded 90mph on a test run somewhere between Leeds and York. It was in the railway press at the time but I don't think that it was on a public service. Of course, I could be mistaken and the unit I remember was a 155 but I don't think so as the 155s were sidelined for months because of a problem with the doors(?). This means that the 156s are (or were) capable of 90 but that they may now be limited by instruction rather than capability as I've been on one on a Barrow to Preston service which seemed to fly once on the WCML although this is very subjective and I only roughly timed a couple of quarter miles.

Drivers tend to stick quite rigidly to unit and line limits these days. As they should.

 

[edwin_m]

I seem to remember that, not long after they were introduced, one unit exceeded 90mph on a test run somewhere between Leeds and York. It was in the railway press at the time but I don't think that it was on a public service. Of course, I could be mistaken and the unit I remember was a 155 but I don't think so as the 155s were sidelined for months because of a problem with the doors(?). This means that the 156s are (or were) capable of 90 but that they may now be limited by instruction rather than capability as I've been on one on a Barrow to Preston service which seemed to fly once on the WCML although this is very subjective and I only roughly timed a couple of quarter miles.

I think that was 1504001, a temporary conversion of 150002 as a testbed for the class 158 powertrain. Reported that the driver of an HST on the fast line was rather surprised to be overtaken by a Sprinter.

 

[hexagon789]

I think that was 1504001, a temporary conversion of 150002 as a testbed for the class 158 powertrain. Reported that the driver of an HST on the fast line was rather surprised to be overtaken by a Sprinter.

Yes 154 001 was the 158 test-bed. It ran at 90, though was still tread-braked to the best of my knowledge. The driving vehicle were both air-conditioned but not the centre car. The driving cars had a standard 285hp Cummins engine, while the centre car had a 350hp Rolls-Royce. The centre car also had a non-standard twin-disc transmission. A right mash-up!

 

[61653 HTAFC]

Yes 154 001 was the 158 test-bed. It ran at 90, though was still tread-braked to the best of my knowledge. The driving vehicle were both air-conditioned but not the centre car. The driving cars had a standard 285hp Cummins engine, while the centre car had a 350hp Rolls-Royce. The centre car also had a non-standard twin-disc transmission. A right mash-up!

150002 was dogged with reliability issues for years since the trial ended, and some might say it still is!

 

[hexagon789]

150002 was dogged with reliability issues for years since the trial ended, and some might say it still is!

I know the twin-disc transmission found little favour

 

[route:oxford]

No they weren't

Ok, so exactly what speed were they going?

Don't forget, every single Class 158 in service on Scotrail was suddenly withdrawn from service en-masse and Scotrail pushed every last unit they had into service. Famously an HST made it onto a local stopping service in Edinburgh.

The 156s had to do their best to match 158 timings on the Aberdeen-Glasgow inter-city runs. Indeed, I recall an incredibly "lively" 101 heritage unit on a non-stop run from Perth to Stirling. It was the first time my ears had ever popped going through the Kippenross tunnel.

 

[hexagon789]

Ok, so exactly what speed were they going?

Don't forget, every single Class 158 in service on Scotrail was suddenly withdrawn from service en-masse and Scotrail pushed every last unit they had into service. Famously an HST made it onto a local stopping service in Edinburgh.

The 156s had to do their best to match 158 timings on the Aberdeen-Glasgow inter-city runs. Indeed, I recall an incredibly "lively" 101 heritage unit on a non-stop run from Perth to Stirling. It was the first time my ears had ever popped going through the Kippenross tunnel.

The 158s were withdrawn because of issues with the disc brakes and kean mulch building up insulating them from track circuits.

 

[randyrippley]

I seem to remember they weren't withdrawn for that: they were simply run with another sprinter or pacer attached which WOULD trigger the track circuits.
They were taken out of service because the chassis suspension mounting points on the body were failing: the welded aluminium structure wasn't strong enough.
As for 156 having the speed limit increased: this was discounted due to the very same clasp brakes which meant they didn't have the track circuit problem.

 

[route:oxford]

I seem to remember they weren't withdrawn for that: they were simply run with another sprinter or pacer attached which WOULD trigger the track circuits.
They were taken out of service because the chassis suspension mounting points on the body were failing: the welded aluminium structure wasn't strong enough.
As for 156 having the speed limit increased: this was discounted due to the very same clasp brakes which meant they didn't have the track circuit problem.

Indeed, something sheared in service, that's why every single one was immediately taken out of service and the SuperSprinters were pushed into taking on all of the Scotrail Express duties - which was following a comprehensive retimtabling to accommodate Scotrail Express differentials, speed and acceleration.

 

[randyrippley]

Indeed, something sheared in service, that's why every single one was immediately taken out of service and the SuperSprinters were pushed into taking on all of the Scotrail Express duties - which was following a comprehensive retimtabling to accommodate Scotrail Express differentials, speed and acceleration.

I'm certain you're wrong. I can remember discussions in the press at the time that said maintaining class 158 speeds wasn't possible because of the clasp brakes: they weren't powerful enough to be safe at increased speeds

 

[hexagon789]

I'm certain you're wrong. I can remember discussions in the press at the time that said maintaining class 158 speeds wasn't possible because of the clasp brakes: they weren't powerful enough to be safe at increased speeds

The 47/7 push-pulls ran at HST differentials where provided and were certainly still permitted to do so even if all the coaching stock was tread braked which happened fairly frequently with the Aberdeen sets.

The 156s as far as I can see were limited to 75 mph even when deputising for the 158s in the early 1990s but presumably could ofset some of the difference in maximum speeds by their improved acceleration.