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Speed limits

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choochoochoo

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ETCS is only on the Cambrian line, the Thameslink core (although not mandatory use on the latter), and the Heathrow branch. It will be appearing on the Moorgate branch next year, and then start appearing more widely.
i doubt it will be on moorgate branch by next year. They've still not got the auto changeover balise at drayton park working after apparently installing it over a year ago.

If they cant get that working yet, what chance have they got with a full on ETCS in the space of a year?
 
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hexagon789

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That doesn't sound great, I thought similar systems where common. Are there any plans to install them on more routes?
TPWS performs much of the intended function to be fair.

And yes, see posts above re further rollout of ERTMS
 

craigybagel

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That doesn't sound great, I thought similar systems where common. Are there any plans to install them on more routes?
It's worth pointing out that statistically the two safest railway networks in Europe are the UK and Ireland. In Ireland, apart from a very limited and basic ATP system fitted only to the electric DART trains running around Dublin, there is no train stop protection at all provided by the signalling stem. The UK as discussed has in the most part got to make do only with TPWS.

And yet the networks are statistically safer then those in Europe, most of which have much more comprehensive train stop and/or overspeed protection.
 

hexagon789

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It's worth pointing out that statistically the two safest railway networks in Europe are the UK and Ireland. In Ireland, apart from a very limited and basic ATP system fitted only to the electric DART trains running around Dublin, there is no train stop protection at all provided by the signalling stem. The UK as discussed has in the most part got to make do only with TPWS.
Ireland also has CAWS on a number of the mainlines which while not providing a train stop function is better than nothing at all.

Ireland is probably where it is on the rankings because until fairly recently the service provision was quite low, even now it's still not a particularly service rich network outside Dublin compared with most Western European countries
 

craigybagel

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Ireland also has CAWS on a number of the mainlines which while not providing a train stop function is better than nothing at all.
Indeed but as there hasn't been much discussion of AWS here I didn't see much point in bringing up CAWS since the latter is essentially just an improved version of the former, and in any case is also only on about half of the Irish network.

Ireland is probably where it is on the rankings because until fairly recently the service provision was quite low, even now it's still not a particularly service rich network outside Dublin compared with most Western European countries
To be fair, yes I'm sure it is something of a statistical anomaly. And certainly IÉ aren't resting on their laurels, given the work taking place at present to both replace CAWS/ATP and provide Train Stop equipment. But they didn't get to that record just by having a quiet network. Passenger numbers have boomed in the last decade, as has the number of services operated - and yet there hasn't been a fatal accident since the Buttevant and Cherryville Junction incidents of the early 1980s.
 

30907

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That doesn't sound great, I thought similar systems where common. Are there any plans to install them on more routes?
ETCS isn't essentially a safety system, though - every national railway had their own before it - AIUI it was developed to simplify through working across national borders, which is less of a problem here :)
 

hexagon789

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Indeed but as there hasn't been much discussion of AWS here I didn't see much point in bringing up CAWS since the latter is essentially just an improved version of the former, and in any case is also only on about half of the Irish network.
I can see your point, I just wanted to make a note of the fact that they do have something on the fastest, busiest mainline sections which at least provides a warning to the driver.


To be fair, yes I'm sure it is something of a statistical anomaly. And certainly IÉ aren't resting on their laurels, given the work taking place at present to both replace CAWS/ATP and provide Train Stop equipment. But they didn't get to that record just by having a quiet network. Passenger numbers have boomed in the last decade, as has the number of services operated - and yet there hasn't been a fatal accident since the Buttevant and Cherryville Junction incidents of the early 1980s.
Also remarkable that none have happened since the switch to non-wooden bodied stock, a change precipitated by those two very accidents.
 

Bald Rick

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ETCS isn't essentially a safety system, though - every national railway had their own before it - AIUI it was developed to simplify through working across national borders, which is less of a problem here :)

ETCS is often misunderstood. It isn’t a signalling system. It is a set of principles, protocols and standards that can be applied as a signalling system.

Much of it was developed in the U.K. I’ve mentioned elsewhere that the first terminus station anywhere in the world with ETCS signalling was Aberystwyth. The U.K. ‘push’ was for a full ATP with speed supervision, and indeed many of the protocols are built on the formative ATP systems in use on GW and Chiltern.

Clearly having a Europe wide agreed set of protocols makes it easier to adopt across the EU - but as we know it has been copied and applied worldwide.
 

Dren Ahmeti

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Historically it did happen, not that infrequently, nowadays only by accident really (the TPE 802 doing over 140mph a wee while back being a case in point).

They do download the OTDR logs from time-to-time to check.
Fairly over 140 as well... nice to know that they go that fast! :lol:
 

Lockwood

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I’ve certainly never driven a car with a 70mph speed limiter.

I have. High spec V70, with a limiter fitted (not always enabled). Get up to speed quickly, then the power just dumps.

With a unit with set speed, does it behave more like modern cruise control limiters and gives extra power when needed (ie set to 60, go up a hill and you don't get any drop, you get to keep 60 from "reserve" power) or like older dodgier ones where it really takes the power off, you get to that hill, slow down a lot because there's no more power and have to build up the speed whilst climbing?
 

AM9

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I have. High spec V70, with a limiter fitted (not always enabled). Get up to speed quickly, then the power just dumps.

With a unit with set speed, does it behave more like modern cruise control limiters and gives extra power when needed (ie set to 60, go up a hill and you don't get any drop, you get to keep 60 from "reserve" power) or like older dodgier ones where it really takes the power off, you get to that hill, slow down a lot because there's no more power and have to build up the speed whilst climbing?
My Mercedes A Class had a CVT gearbox with a limiter/cruise control. The cruise range was between 20 and 75 mph and I believe that the limiter covered the same range, (it was the same electronics working in reverse logic). When in limiter mode, the engine wouldn't rspond to more throttle depression above the set speed. Interestingly, the cruise mode would maintain speed uphill (by reducing the transmission ratio when there wasn't enough torque - until the maximum permissible rpm was reached) and interestingly, it would also 'change down' when descending a steep hill to create more engine braking to maintain the set speed. That was great for forcing tailgaters to keep back and I didn't need to touch the brakes. They quickly gave up trying to intimidate me to go faster!
 

cambsy

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Have LNER and GWR drivers been having same thing happen as TPE did with their 145mph plus incident? Or is there now a an Hitachi 8xx series, 140mph club, like existed when the HST first ran on the GWR and the 91’s first came out.
 

gimmea50anyday

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Lol, are they having a competition! ;)

Sounds like BR drivers when the HSTs were new.
Lol, no but a clear indication perhaps that there is something amiss in the design, setup or operation of the trains that allows them to overspeed in such a manner especially where other train types have speed limitations in place.
 

Dren Ahmeti

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Lol, no but a clear indication perhaps that there is something amiss in the design, setup or operation of the trains that allows them to overspeed in such a manner especially where other train types have speed limitations in place.
A bit more over 10% overspeed o_OThe IET’s have a speed set, yet nothing actually stops them over-speeding (unless you’re on the Western and you’re under ATP supervision) as they are probably allowed the “overspeed” for 140mph running under ETCS.
 

hexagon789

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Lol, no but a clear indication perhaps that there is something amiss in the design, setup or operation of the trains that allows them to overspeed in such a manner especially where other train types have speed limitations in place.
I've seen a report that the RAIB are aware of a number if overspeed incidents with these units and that Hitachi are being asked to consider installing some form of limiter software.
 

AlexNL

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If the train is holding the service speed at 200kmh then that would make sense as far as any cruise control/speed set/speed limiter is concerned as the computers will be working logically (no pun intended) in metric.
Somewhat offtopic but still somehow related:
In my car, an Opel Mokka X (Vauxhall in GB), I've noticed that I can set the cruise control and the limiter in 2 km/h increments only. Sometimes it increments by 3 km/h, and then continues again in 2 km/h increments.

I've also found out that the maximum speed I can set it to is an awkwardly specific number: 204 km/h.

After pondering over why this might be for a while, I think I've figured it out: the onboard computer uses mi/h internally and just converts the number for display purposes.

My assumption is t GM's software engineers store the set speed in 7 bits and use mi/h for that. 204 km/h = 127 mi/h = 111 1111 in binary. :D
 

Lockwood

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My assumption is t GM's software engineers store the set speed in 7 bits and use mi/h for that. 204 km/h = 127 mi/h = 111 1111 in binary. :D
I was going to suggest it was stored in an 8 bit signed int, which would have the same effect. I then got a lughtbulb moment. Store it as an 8 bit value with the MSB acting as an enabled flag and the other 7 storing speed?
 

ABB125

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I was going to suggest it was stored in an 8 bit signed int, which would have the same effect. I then got a lughtbulb moment. Store it as an 8 bit value with the MSB acting as an enabled flag and the other 7 storing speed?
You could save all this bother by using an on/off toggle switch and a big potentiometer on the dashboard... :D:D
 

TRAX

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Somewhat offtopic but still somehow related:
In my car, an Opel Mokka X (Vauxhall in GB), I've noticed that I can set the cruise control and the limiter in 2 km/h increments only. Sometimes it increments by 3 km/h, and then continues again in 2 km/h increments.

I've also found out that the maximum speed I can set it to is an awkwardly specific number: 204 km/h.

After pondering over why this might be for a while, I think I've figured it out: the onboard computer uses mi/h internally and just converts the number for display purposes.

My assumption is t GM's software engineers store the set speed in 7 bits and use mi/h for that. 204 km/h = 127 mi/h = 111 1111 in binary. :D

Your hypothesis is interesting, but may I add that most cars don’t have a nice rounded number as their top speed.

And, rather elegantly, one of the models in the Peugeot 208 range has a 208 km/h top speed.
 

Wookiee

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Back in the late 80s, I can recall passing by the middle cabs of a pair of TCs double-headed by 73s - as we exited the Popham tunnels southbound, the speedo in one of the cabs was reading a fraction under 110mph. Was never really sure if that was likely to be accurate or not, in the circumstances, i.e. not being the driving cab, but it did feel like we were going at a hell of a rate!
 

delticdave

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A Japanese car; with a CVT gearbox. Ouch. That sounds like an (automotive) fate worse than death.
Try driving the mild hybrid version of the Toyota CHR, it's "interesting"...

To be fair though, a Mazda Demio was quite fun in Cyprus, even in the mountains.

I’m sure there’s an extremely simple answer to this question but why are trains even capable of exceeding the maximum speed they will encounter in the UK? Why doesn’t an HST just cut power at 125mph like the speed limiter in a car?
If you own a car with a speed limiter it's your choice to switch it on & then the limit of your choice. Cruise is different, you can always exceed the selected cruising speed, the gas pedal still works...

My oldest car doesen't have a limiter, just the basic cruise control, adaptive cruise is fitted to the newer beastie, that will bring the car to a halt if necessary.
 
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