Train horn reliability

[AndrewE]

We seem to have a new Achilles' heel now:

I wonder how many other incidents were indirectly affected (or possibly caused) by the 20mph if horn not working rule?- there must have been hundreds if not thousands of failures across the network.
I seriously hope once this all settles down that a redesign, temp fix or a rule book change comes out of this.

Rule book change? It's a warning horn on a train, aside from the brakes it's the most important safety critical device on there. I have driven a train for 25 miles with a completely defective warning horn at 20mph, that was fast enough for me. The rulebook instructions are there for a reason, just because they cause inconvenience it doesn't mean there's anything wrong with them.

It seems that a redesign or modification might be worthwhile if horn failure is turning out to be a significant factor causing the collapse of services.
Given the power available nowadays maybe have them pointing downwards or backwards against a reflector plate? Or worked by a miniature instant steam generator to provide its own defrost mechanism! (posted here to avoid being deleted as off-topic in the New Forest thread)

 

[Darkinsider]

deleted

 

[superkev]

Give the drivers a tin of de-icer to save calling the fitter who use theirs. Also works with frozen unbagged couplings.
K

 

[irish_rail]

Had it yesterday. Baffled as to why it appears to be the high tone that is affected and low tone no problems. Turbostar family of train tbw.

I had the opposite yesterday high tone fine low tone a goner.

 

[AndrewE]

Give the drivers a tin of de-icer to save calling the fitter who use theirs. Also works with frozen unbagged couplings.
K

Good idea... but how heavy is the satchel now?

 

[edwin_m]

Good idea... but how heavy is the satchel now?

Could keep it in a cabinet somewhere, like all the other items of safety equipment that have to be carried on each train.

 

[AlexNL]

Given the power available nowadays maybe have them pointing downwards or backwards against a reflector plate?

Wouldn't the reflector plate suffer from the same problem that the horns suffer from now, i.e. buildup of snow rendering them useless?

Pointing the horns downwards might work, but then the audio directionality would be lost and they would be less effective.

 

[AndrewE]

Wouldn't the reflector plate suffer from the same problem that the horns suffer from now, i.e. buildup of snow rendering them useless?

Pointing the horns downwards might work, but then the audio directionality would be lost and they would be less effective.

I would think that a smart bit of aerodynamics design expertise could give you a wind-tunnel (funnel) that took the snow through a channel (or two) leaving the horn mouth and reflector clear. Sounds like a very good MSc or PhD project for a rolling stock company or NR to support/sponsor if you ask me (not that anyone would!)

 

[scott118]

Could keep it in a cabinet somewhere, like all the other items of safety equipment that have to be carried on each train.

They'd end up in the staff members cars, ready for when they are running late on that early shift, or can't wait 5 mins to defrost the car properly on their way home..

 

[brel york]

I would think that a smart bit of aerodynamics design expertise could give you a wind-tunnel (funnel) that took the snow through a channel (or two) leaving the horn mouth and reflector clear. Sounds like a very good MSc or PhD project for a rolling stock company or NR to support/sponsor if you ask me (not that anyone would!)

There’s loads of variation, I’ve seen pointed deflectors, grills , cloth , nothing at all , all on the same type of horn

 

[AndrewE]

There’s loads of variation, I’ve seen pointed deflectors, grills , cloth , nothing at all , all on the same type of horn

But how much smart thinking went into any of them?

 

[AlexNL]

Probably a lot.

There's also the matter of a cost/benefit ratio. While it might be possible to design a horn which can withstand a blizzard, is it worth doing so if the situations which necessitate such a horn only occur once every year?

It might be worth looking at how this is dealt with in countries which see a lot more wintery circumstances than the UK. Take Norway for example: they have trains running above the Arctic circle. How are their horns designed?

 

[AndrewE]

Probably a lot.

given the descriptions "pointed deflectors, grills , cloth , nothing at all" I would suggest that the answer is more likely "not a lot!" They are all the things that I or an engineering friend on a depot might come up with based on our own ideas or experience... Which is why I suggested a bit of deeper thought.

There's also the matter of a cost/benefit ratio. While it might be possible to design a horn which can withstand a blizzard, is it worth doing so if the situations which necessitate such a horn only occur once every year?

agreed, but if something robust is built in it doesn't cost anything after the initial design and build (and might save the day or prevent worse disruption) then why not do it?

It might be worth looking at how this is dealt with in countries which see a lot more wintery circumstances than the UK.

Definitely worth doing.

 

[37057]

given the descriptions "pointed deflectors, grills , cloth , nothing at all" I would suggest that the answer is more likely "not a lot!"

Actually a lot has. Including mock ups and wind tunnels... and the fitting of trace heating.

 

[XDM]

20 mph seems very restrictive for no horn operation. Sure, it should be 20 mph over crossings, which are much rarer these days on main lines. But in daylight it could be 40 or 45 mph elsewhere which gives ample time to slow to 20 mph if Hi viz jackets are seen ahead. Route knowledge is about knowing where crossings are.

 

[edwin_m]

20 mph seems very restrictive for no horn operation. Sure, it should be 20 mph over crossings, which are much rarer these days on main lines. But in daylight it could be 40 or 45 mph elsewhere which gives ample time to slow to 20 mph if Hi viz jackets are seen ahead. Route knowledge is about knowing where crossings are.

I'd have thought you'd have to stop short of any track workers - it's surprisingly hard to hear an approaching train if, for example, it's electric and there is background noise from a nearby road. Slowing from 40mph to 20mph won't make any difference to the outcome if the train hits them at that speed.

 

[scott118]

20 mph seems very restrictive for no horn operation. Sure, it should be 20 mph over crossings, which are much rarer these days on main lines. But in daylight it could be 40 or 45 mph elsewhere which gives ample time to slow to 20 mph if Hi viz jackets are seen ahead. Route knowledge is about knowing where crossings are.

Not every one on the railway, wears a hi-viz.

 

[dk1]

Give the drivers a tin of de-icer to save calling the fitter who use theirs. Also works with frozen unbagged couplings.
K

Bombardier always left a huge tin in the 170s when they maintained the AR/NXEA fleet.

 

[SPADTrap]

20 mph seems very restrictive for no horn operation. Sure, it should be 20 mph over crossings, which are much rarer these days on main lines. But in daylight it could be 40 or 45 mph elsewhere which gives ample time to slow to 20 mph if Hi viz jackets are seen ahead. Route knowledge is about knowing where crossings are.

The idea is that it is restrictive.

 

[t_star2001uk]

A majority of Chiltern 168s had the horns turned to face backwards with no adverse affect to the sound.

 

[XDM]

I'd have thought you'd have to stop short of any track workers - it's surprisingly hard to hear an approaching train if, for example, it's electric and there is background noise from a nearby road. Slowing from 40mph to 20mph won't make any difference to the outcome if the train hits them at that speed.

20 mph is in the rule book because a modern passenger train can stop on sixpence at that speed. The suggestion of reducing the speed from the proposed daylight 40mph to 20 mph when high viz are in the track was that if you are not acknowledged you can stop on that sixpence before you reach them. People I have mentioned it to think it is a good idea. Remember there are unknown downsides to travelling at 20 mph all the time. It could have been a catastrophe at Christchurch if evacuating passengers had got onto the track in the dark. Apparently the first train stuck because 20 mph did not give its shoes enough momentum to clear the third rail ice or propel the train though iced up sections.

 

[Pete_uk]

The obvious answer is to have a heating system on the horns

 

[dk1]

The obvious answer is to have a heating system on the horns

That would need to be some sort of powerful outside heater running head on into cold air at high speed. Wouldn't work.

 

[IanXC]

A majority of Chiltern 168s had the horns turned to face backwards with no adverse affect to the sound.

This seems a very interesting concept, sounds like a cheap, practical solution.

 

[driver9000]

That would need to be some sort of powerful outside heater running head on into cold air at high speed. Wouldn't work.

Transpennine 350s have heated horns and couplers which seem to work ok. The horns are also behind a shield.

 

[theageofthetra]

Transpennine 350s have heated horns and couplers which seem to work ok. The horns are also behind a shield.

A very sensible idea that wasn't applied to the new 700's.

Did we have these issues when horns were roof mounted?

 

[Rail Blues]

A heating system on the horns may be an obvious solution, bit a difficult and expensive one to retrofit. If it was that straightforward it would have been done already.

Like anything you could probably snow proof the horns of every unit on the network if you had a bottomless pit of money. In the absence of this, retrofitting equipment that may be useful once every other year hardly seems a sound investment.