TPWS Intervention - Disciplinary action?

[eaglestarlight]

Greetings from the west side of the pond!

I'm a driver ("engineer") for a passenger railroad in the US. Our version of TPWS is broadly referred to as Positive Train Control ("PTC"), and there are two distinct systems that can be used, depending on the line in question.

When PTC first began to be cut-in on our lines, drivers were getting penalties left-and-right since the braking algorithm was (and is, especially on the newer implementation of PTC) quite conservative. Most companies were somewhat lenient at first, but there is a steady progression towards imposing discipline for "at fault" PTC penalties (charging up on a curve too rapidly or over-accelerating out of a restriction being the 2 most common.)

Thus, I got to thinking: how are TPWS interventions handled on the UK network? How do they compare to actually SPADing (for instance?) As an aside, here "getting by a red" (our colloquial term for SPADing) carries a minimum 30 day suspension of license, as well as any other discipline imposed by the carrier. The penalty for PTC penalties isn't so clear cut - although you can expect to have some unpaid time off once you rack up more than 1 or 2 in a certain timeframe.

Just curious to see how things are treated on different networks.

 

[NSEWonderer]

They're treated fairly seriously but there is differing levels of TPWS kicking in . The first is an Activation. Driver basically was braking or doing something but not enough for the grids. An intervention is basically when the driver does nothing and the system kicks in, that's the more serious of the two as essentially had the system not intervened there would've been potentially nothing to slow down or stop the train for the danger ahead.

 

[Javelin_55]

TPWS interventions are treated fairly seriously, as you'd expect (they can be just as dangerous as SPaDs if the speed is high enough), but the major focus will be on why it happened, and how to prevent it next time. I imagine the process differs slightly from company to company, but generally speaking the driver will be "off track" for as long as it takes to investigate what happened, have a meeting about next steps, draw up a plan of action, and get it all signed off.

Here if you start racking up incidents then there will certainly be a conversation had about whether you're suited to the role - but I haven't heard of unpaid leave and suspension of licence unless the driver is about to be canned.

Are you East coast based? Something jogged my memory yesterday about the Hoboken train crash in 2016 and I looked it up. Even after that, it looks like PTC hasn't been installed there, but I couldn't find an update as to what happened to the engineer.

 

[eaglestarlight]

TPWS interventions are treated fairly seriously, as you'd expect (they can be just as dangerous as SPaDs if the speed is high enough), but the major focus will be on why it happened, and how to prevent it next time. I imagine the process differs slightly from company to company, but generally speaking the driver will be "off track" for as long as it takes to investigate what happened, have a meeting about next steps, draw up a plan of action, and get it all signed off.

Here if you start racking up incidents then there will certainly be a conversation had about whether you're suited to the role - but I haven't heard of unpaid leave and suspension of licence unless the driver is about to be canned.

Are you East coast based? Something jogged my memory yesterday about the Hoboken train crash in 2016 and I looked it up. Even after that, it looks like PTC hasn't been installed there, but I couldn't find an update as to what happened to the engineer.

Yes I am; NYC-based in fact. I don't know specifically what happened to the NJ Transit engineer that overran the bumping post at Hoboken, but I think he would have perhaps been medically disqualified due to the sleep apnea issue. Conversely, I -do- know that the engineer of the ill-fated train 188 (Philadelphia derailment in 2015) was terminated and as far as I know, his chances of returning are quite slim indeed.

== Doublepost prevention - post automatically merged: 25 Feb 2026 ==

They're treated fairly seriously but there is differing levels of TPWS kicking in . The first is an Activation. Driver basically was braking or doing something but not enough for the grids. An intervention is basically when the driver does nothing and the system kicks in, that's the more serious of the two as essentially had the system not intervened there would've been potentially nothing to slow down or stop the train for the danger ahead.

It's interesting to learn there's a difference between an activation and an intervention. We have pretty much the exact thing there, "Type 1" penalties (which are similar to an activation), and "Type 2" penalties which are defined as either:

-ODTR shows driver did not make any attempt to slow/stop the train prior to the penalty/intervention

-"Reactive" penalty for 5+ MPH over the speed

We are "allowed" 2 Type 1s in a rolling 6-month period. First (and subsequent) type 2s are formal discipline (and we don't even get tea, let alone biscuits during our driver manager meetings haha.) But even Type 1s can be seriously problematic for engineers operating on rails not owned by their employing railroad.

My railroad is decent, the freight carriers here are not, and they're quite trigger happy to ban foreign railroad engineers for their first activation (and of course, it's guilty until proven innocent.)
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It's nice to see an environment that appears to value safety more than punishment and intimidation. We do have a "Close Call" reporting system that protects us from discipline for -some- violations (as long as we voluntarily take responsibility and provide statements to help decrease the likelihood of it happening again), but there's rumors that may going the way of the dodo soon.

Not that anyone asked, but both I-ETMS and ACSES give advance warning of an impending penalty. I-ETMS has a "time to penalty" countdown timer, which sounds great in theory, but still requires far too much focus on the screen. The timer starts at 30 seconds and adds additional time (longer time until penalty) when the driver reduces the throttle, applies the brakes, etc. This is due to the fact that I-ETMS considers the current control stand inputs in addition to the grade, current speed, etc. lThe biggest issue I have had with such a system (and thankfully I don't operate under it anymore) is how finicky and I consistent the timer is (because of the consideration of throttle/brake positions.) Say you're within a train-length of the restriction being protected. If we release the brakes in anticipation of the speed being achieved by the time the release propogates the entire train, the system may go bonkers and give you the seconds like "14, 9, 3, 1, POW" activation. Thus, even after having run with it for over a year, I still found the screen pulling my eyes off the rails ahead.

ACSES is much better - it gives you a speed that follows the braking curve. So at 125 MPH approaching a 90 MPH bend, the authorized speed display with go "125, 124, 123..." and so on, thus making it much easier to steal quick glances at to make sure its satisfied. The speed countdown is almost 100% linear and is unaffected by any control inputs, thus allowing the driver to focus on running the train rather than appeasing an overzealous computer.

Thank you for the insight and sorry for the long-winded post; I recently took LNER just to Peterborough from Kings Cross just to sample your railways - far more useful than ours haha.

 

[NSEWonderer]

Yes I am; NYC-based in fact. I don't know specifically what happened to the NJ Transit engineer that overran the bumping post at Hoboken, but I think he would have perhaps been medically disqualified due to the sleep apnea issue. Conversely, I -do- know that the engineer of the ill-fated train 188 (Philadelphia derailment in 2015) was terminated and as far as I know, his chances of returning are quite slim indeed.

== Doublepost prevention - post automatically merged: 25 Feb 2026 ==


It's interesting to learn there's a difference between an activation and an intervention. We have pretty much the exact thing there, "Type 1" penalties (which are similar to an activation), and "Type 2" penalties which are defined as either:

-ODTR shows driver did not make any attempt to slow/stop the train prior to the penalty/intervention

-"Reactive" penalty for 5+ MPH over the speed

We are "allowed" 2 Type 1s in a rolling 6-month period. First (and subsequent) type 2s are formal discipline (and we don't even get tea, let alone biscuits during our driver manager meetings haha.) But even Type 1s can be seriously problematic for engineers operating on rails not owned by their employing railroad.

My railroad is decent, the freight carriers here are not, and they're quite trigger happy to ban foreign railroad engineers for their first activation (and of course, it's guilty until proven innocent.)
------------
It's nice to see an environment that appears to value safety more than punishment and intimidation. We do have a "Close Call" reporting system that protects us from discipline for -some- violations (as long as we voluntarily take responsibility and provide statements to help decrease the likelihood of it happening again), but there's rumors that may going the way of the dodo soon.

Not that anyone asked, but both I-ETMS and ACSES give advance warning of an impending penalty. I-ETMS has a "time to penalty" countdown timer, which sounds great in theory, but still requires far too much focus on the screen. The timer starts at 30 seconds and adds additional time (longer time until penalty) when the driver reduces the throttle, applies the brakes, etc. This is due to the fact that I-ETMS considers the current control stand inputs in addition to the grade, current speed, etc. lThe biggest issue I have had with such a system (and thankfully I don't operate under it anymore) is how finicky and I consistent the timer is (because of the consideration of throttle/brake positions.) Say you're within a train-length of the restriction being protected. If we release the brakes in anticipation of the speed being achieved by the time the release propogates the entire train, the system may go bonkers and give you the seconds like "14, 9, 3, 1, POW" activation. Thus, even after having run with it for over a year, I still found the screen pulling my eyes off the rails ahead.

ACSES is much better - it gives you a speed that follows the braking curve. So at 125 MPH approaching a 90 MPH bend, the authorized speed display with go "125, 124, 123..." and so on, thus making it much easier to steal quick glances at to make sure its satisfied. The speed countdown is almost 100% linear and is unaffected by any control inputs, thus allowing the driver to focus on running the train rather than appeasing an overzealous computer.

Thank you for the insight and sorry for the long-winded post; I recently took LNER just to Peterborough from Kings Cross just to sample your railways - far more useful than ours haha.

Haha no worries. All good to see the differences and similarities.