My idea for linear eddy current brakes

[HSTEd]

The obvious technical solution here is linear eddy current brakes for emergency use.

But that would probably only be practical on new stock and could get very expensive infrastructure wise. But it would stop high speed sliding SPAD incidents like this from happening.

Certainly cheaper than the never ending war on vegetation oft proposed instead

 

[furnessvale]

The obvious technical solution here is linear eddy current brakes for emergency use.

But that would probably only be practical on new stock and could get very expensive infrastructure wise. But it would stop high speed sliding SPAD incidents like this from happening.

Certainly cheaper than the never ending war on vegetation oft proposed instead

That will stop trains, but if we give up on fighting vegetation, how do we get them moving on heavily contaminated rails. Not only that, but alternatives to track circuits would also have to be installed nationwide.

Trees also have a nasty habit of falling over. The only answer is to remove EVERY tree situated where, if it falls, it can obstruct a running line whether on railway property or elsewhere. It will be a big job, we have a backlog since 1968 to address!

 

[Falcon1200]

The only answer is to remove EVERY tree situated where, if it falls, it can obstruct a running line whether on railway property or elsewhere. It will be a big job, we have a backlog since 1968 to address!

Fair enough, albeit at huge cost and almighty local opposition, but can the same principle and standard be applied to every road in the country, given that during the recent multiple storms no rail staff or passengers were killed by fallen tree incidents, but three motorists sadly were ?

I don't think the blame lies with any of the operational staff involved.

I agree absolutely.

For me, there are some questions nor addressed in the interim report but which will, hopefully, be in the final version;
Was there a history of exceptionally poor railhead conditions at this location; or wrong side TC failures caused by railhead contamination ?
Indeed, did any wrong side TC failures occur on the day of the accident, or during it ?
Had there been any previous reports of poor adhesion at this location, on the day itself or at any other time ?
Were there previously similar intervals between RHTT runs over this section, and if so were there any adverse effects ?

Regarding previous comments that NR regard the RHTT as an annoying inconvenience, I can only say that this was not my experience: NR spends a huge amount of time and money organising and running these trains, recognising that they are vital to maintaining both safety and performance during times of anticipated poor railhead conditions.

 

[Nottingham59]

can the same principle and standard be applied to every road in the country

When was the last time you saw trees overhanging a motorway?

 

[Falcon1200]

When was the last time you saw trees overhanging a motorway?

Motorways are a tiny fraction of the UKs road network. But actually, I do agree that NR needs to do more to tackle lineside vegetation, but there are practical limits on how much can be done, eg time, money, staff, lineside access, neighbour opposition, etc, and there will never be a time when every tree near enough a railway to fall on it will be removed.

 

[stuu]

When was the last time you saw trees overhanging a motorway?

The M4 west of Reading has loads. Generally the oldest sections of motorways which haven't had any major widening or anything have plenty of trees close enough to cause problems if they fell down

 

[MarkyT]

The obvious technical solution here is linear eddy current brakes for emergency use.

But that would probably only be practical on new stock and could get very expensive infrastructure wise. But it would stop high speed sliding SPAD incidents like this from happening.

Certainly cheaper than the never ending war on vegetation oft proposed instead

I'd opt for magnetic friction track brakes on most trains for emergency use. Eddy current retardation fades dramatically as you get slower dropping to no effect whatsoever near zero speed, so is useful for avoiding wear in initial heavy braking from high speed but useless for final stopping. Magnetic brakes stay fully engaged.

 

[furnessvale]

Fair enough, albeit at huge cost and almighty local opposition, but can the same principle and standard be applied to every road in the country, given that during the recent multiple storms no rail staff or passengers were killed by fallen tree incidents, but three motorists sadly were ?

A major reason no rail staff or passengers were killed is that the railways virtually stopped running, a situation which cannot be repeated every time the wind blows.

The road authorities can make their own justifications for their actions. Rail has a different braking profile and does not rely on line of sight like roads.

Rail also has a much higher expectation of safety. Three deaths on the railway would stop the job for a fortnight. Three deaths on the roads are only a part of the daily toll.

 

[HSTEd]

I'd opt for magnetic friction track brakes on most trains for emergency use. Eddy current retardation fades dramatically as you get slower dropping to no effect whatsoever near zero speed, so is useful for avoiding wear in initial heavy braking from high speed but useless for final stopping. Magnetic brakes stay fully engaged.

Magnetic track brakes don't help very much in a low adhesion situation though, and the ICE eddy current brakes only reach zero braking effort at 50km/h ~30mph.
In the situation that prompted this original comment the failure of braking became apparent at well over 80mph, extra brake force that would definitely be available down to 30mph would substantially improved the train's situation!

== Doublepost prevention - post automatically merged: 23 Feb 2022 ==

That will stop trains, but if we give up on fighting vegetation, how do we get them moving on heavily contaminated rails.

That converts this from a safety problem to an operational nuisance.

Not only that, but alternatives to track circuits would also have to be installed nationwide.

Track circuits are already well on the way to being in the dustbin, with ever-increasing employment of axle counters regardless!

Trees also have a nasty habit of falling over. The only answer is to remove EVERY tree situated where, if it falls, it can obstruct a running line whether on railway property or elsewhere. It will be a big job, we have a backlog since 1968 to address!

Leaving aside that the railway has no power to do anything to vegetation outside the boundary fence, which in many cases is very close to the actual railway, it would be astronomically expensive.
This is not the old world where you can hire an unlimited supply of irishmen to do days of backbreaking labour for a pittance.

Even attempting this would eat billions every year, even at equilibrium. Plus the disruption from periodical total line closures to do anything on the trackside.