OT: Steering a train?

[Dave]

OK on that, I understand a lot better now

Dave

[Frank Erskine]

How do you steer a train?

[nightjar]

That is precisely the point where this thread started. However, on a train, the other advantage of an anti-lock braking system is the important one - you don't get flats worn on the tyre during braking, leaving the members of the Wheeltappers and Shunters' Club to drink their beers in peace.

Colin Bignell

[Frank Erskine]

Aren't these electric trains? If so, as soon as the locomotive leaves the track/overhead wires, won't it stop pretty quickly?

Do electric trains have ABS, or is this all just BS?

[Andy Dingley]

Because if the wheels are rolling, you can still steer.

For rubber car tyres, locked and smoking will easily out-brake a rolling wheel. However you're pretty much out of control at this point.

[nightjar]

...

However, is there really any justification for them being leading points? Trailing points would be a lot safer and would be quite adequate for train recovery and short-term single line working. If it is felt necessary for leading points to be available for long-term single line working, that could be accommodated by having the controls and signals in place and the points substantially in place, but without point blades and with the first section of curved rail and the frog replaced by a section of straight rail welded in place. Bringing the points into use for long term use would then only require the rail to be cut and a short section of curved rail to be fitted, along with the frog and blades. Afterwards, the site could be returned to its original condition. Safety would be improved and maintenance reduced.

Colin Bignell

[Dave Plowman (News)]

This isn't so. A smoking road tyre indicates melted rubber which acts as a lubricant. Different matter with tyres specially designed for drag racing etc.

[Julian]

Yup, you rely on a wedge of snow building in front of the locked wheel. I've an old Audi with ABS, the driver has a switch to disable the system when road condition are as you suggest.

The disable facility doesn't feature in modern cars. If the average driver can't work out how to operate the fog lights properly then they haven't a hope in hell with the ABS switch!

_Very_ early ABS systems, like the Dunlop Maxaret, (pinched from aeroplanes) had some issues. ISTR a violent kicking through the pedal when the system operated.

Julian.

Julian.

[Dave Plowman (News)]

It's automatic - they all cut out at low speed. Which is the only time building up a wedge of snow would help stop anyway.

I'm not sure it would comply with current regs anyway.

All ABS systems cause the pedal to kick when they operate.

BTW - I'm not quite sure what you mean by 'pinched'. Dunlop made the system for aeroplanes so it was just an extension of application. Which was waiting for a suitable AWD drive system. So the credit really went to Ferguson.

[Julian]

No, it can happen at any speed. Audi describe this at length in the handbook. And again, the Audi system cuts out below about 10mph, irrespective of system switch position.

Don't know, probably not.

Notice the word _violent_. I used it for a reason. Modern systems provide a 'pulsing' sensation through the pedal.

Don't bugger around with words, it's a newsgroup, not some sort of legal documentation FFS!

[David Hansen]

On Tue, 27 Feb 2007 08:30:55 -0000 someone who may be "nightjar" wrote this:-

The justification is that it avoids reversing over trailing points, an operation not without dangers.

That is addressing the wrong area and taking us back to the Victorian era when there was a horror of facing points.

Facing points have existed as long as there have been railways and it makes no sense to artificially reduce their number. Rather it is important to understand what has gone wrong in this and other crashes and do what is possible to reduce the chances of it happening again. However, these chances can not be reduced to zero.

Even if 100% safety was possible it would not be desirable. The only way to achieve it would be to remove the railway altogether and return the land to its former use. Even if there are no tracks people can still fall off bridges so there is not 100% safety even with no tracks.

[Andy Burns]

Lexus GS300 has "snow mode" switch for traction control, I'd be surprised if it doesn't talk to ABS too.

[David Hansen]

On Tue, 27 Feb 2007 01:09:27 +0000 someone who may be Frank Erskine wrote this:-

Any type of train will stop much more quickly if it is off the rails than if it is on them.

New designs of train have had wheelslide protection since the early

1970s, it might even be the very late 1960s. As well as preventing flat tyres it has an advantage at least as important, the braking rate can be increased to nearer that of the limit of friction between the wheels and rails. In older braking systems there was a larger gap between the maximum braking rate and the friction limit to allow for patches of rail where the friction was less, which would cause the wheels to start sliding from which they would not recover when the patch ended.

With wheelslide protection the braking on an individual axle is reduced as it starts to slide, so the wheel continues revolving and braking is then increased again as the axle picks up speed again after the bad patch. A train can pass over a bad patch with the braking rate being varied automatically as individual axles pass over the bad patch. This all happens in a fraction of a second.

It is one of the reasons why "modern" trains, for example the High Speed Train designed in the early 1970s, can stop from 125mph in a little less than the distance which earlier trains took to stop from

100mph.

[manatbandq]

The correct term is "facing points". What are trailing points when you reverse over them, if not facing (in the other direction of travel)? A crossover *always* has one facing and one trailing point.

If the points are defective (as seems to be the case here) then they are faulty and can cause a derailment, regardless if the direction they face.

Facing points are very safe when (like any other track) they are maintained properly and negotiated within the safe speed limit. A century and a half of development and facing point locks see to that.

Now, the real question is how many were killed and injured on the roads that day?

Why are those deaths less tragic or less newsworthy than the single fatality in the derailment?

Why doesn't the transpport minister or a car manufacturer come on the TV to talk about the brave drivers that tried their best to avoid a fatal collision?

Why don't we discuss it here, every single day of the year?

Whay are =A3billions spent in knee jerk reactions on TPWS, ATP, and the like, when a far greater payback, in terms of lives, could be achieved by spending it on road safety measures?

MBQ

[Dave Fawthrop]

|!Now, the real question is how many were killed and injured on the |!roads that day?

The average daily death toll on the roads is ten, but reducing and now probably nine, as governments of all colours improve road s and introduce safety legislation. The death toll was 20 per day when I first took an interest

|!Whay are ?billions spent in knee jerk reactions on TPWS, ATP, and the |!like, when a far greater payback, in terms of lives, could be achieved |!by spending it on road safety measures?

Billions *are* spent on road improvements

[AJH]

So this is what happened here?

How often are points inspected? They missed one inspection on Feb 18 but there was one 6 days before, so why was one rod and several bolts missing. OK it's not D-I-Y but wouldn't a train operator be able to photograph points on the fly and have a bot do a comparison for missing bits?

AJH

[David Hansen]

On Tue, 27 Feb 2007 13:09:35 +0000 someone who may be AJH wrote this:-

A Network Rail inspection passed the crossover a few days before. One of the things that will be looked at is the recordings of what its cameras saw. This should establish whether all the stretcher bars were properly in place at the time it passed, but not the condition of the nuts.

[Nick]

Well, in N.E. Hampshire, Hart council has just spent tens of thousands (?) well about 4 months of many workers and big machines, creating road hazards - all in the name of "safety" apparently, according to Highways in Winchester.

Several deliberate kinks have been introduced with sharp pavement edges, central reservations and road narrowings, to "reduce the speed of traffic" they said.... One thing for sure is that it is very hazardous, lots of sudden braking and cars are hitting kerbs hard enough now to wreck tyres and wheels, and the other day there were two accidents in one day - a cyclist was knocked off when the two car drivers realised there was not enough room for all three of them to pass.

It incenses me to see money being spent creating hazards and then more being spent putting people back together again, when previously it was pretty much OK.

They could have achieved the aim more quickly and cheaply with even more speed cameras and got some revenue as well without causing damage to property and maiming people - isn't there a law against that ?

Nick

[Dave Fawthrop]

|!> |!Whay are ?billions spent in knee jerk reactions on TPWS, ATP, and the |!> |!like, when a far greater payback, in terms of lives, could be achieved |!> |!by spending it on road safety measures? |!>

|!> Billions *are* spent on road improvements |!> -- |!> Dave Fawthrop Compare and contrast |! |!Well, in N.E. Hampshire, Hart council has just spent tens of thousands (?) |!well about 4 months of many workers |!and big machines, creating road hazards - all in the name of "safety" |!apparently, according to Highways in Winchester. |! |!Several deliberate kinks have been introduced with sharp pavement edges, |!central reservations and road narrowings, to "reduce the speed of traffic" |!they said.... One thing for sure is that it is very hazardous, lots of |!sudden braking and cars are hitting kerbs hard enough now to wreck tyres and |!wheels, and the other day there were two accidents in one day - a cyclist |!was knocked off when the two car drivers realised there was not enough room |!for all three of them to pass. |! |!It incenses me to see money being spent creating hazards and then more being |!spent putting people back together again, when previously it was pretty much |!OK. |! |!They could have achieved the aim more quickly and cheaply with even more |!speed cameras and got some revenue as well |!without causing damage to property and maiming people - isn't there a law |!against that ?

You use a strange, indeed obtuse definition of hazard.

[Roger Mills]

How else would you describe driving along a straight road, minding your own business, and suddenly being confronted with a kerb which blocks most of your half of the road.

One of the many definitions of 'hazard' in my dictionary is "source of danger". Covers it rather well, I feel!

Lets leave the obtuse definitions to those road engineers who believe they are contributing to road safety by making the roads more dangerous. Perhaps they went to the same school as the Prime Minister - but don't get me started on Iraq!