Trainstop Failures

[Colin]

Perhaps one for aetearlscourt or Tom........

I know that when a trainstop fails (obstruction or loss of air), it not only causes a dual aspect but also the signal in rear to remain at danger too.

So far, so so good.

So let's take an example: station starter trainstop fails causing the home(s) to remain at danger.................what if there was a draw-up associated with the starter; would that also remain at danger, or would it carry on operating as it normally would (ie, because it can draw trains up slowly)?

[Deleted]

well if the trainstop fails and its the TQ failure 1's contact in the trainstop this would cause the replacing track (next one after the signal) to fail
2's contact is usually the same but in a control site area
3's picks up the PGR repeating signal relay
4's just does the lights (suspression)
5's is the other feed for the red light (this is where you get the dual aspect from)

1,2,5 are ON contacts (trainstop up)
3,4 are OFF contacts (trainstop down)

but going back to your question im sure in the selection for a draw up it has to see the tracks upto the next signal to be up aswell but without looking at a print for a draw up signal i cannot confirm this but it would make sense but who knows every site is diffferent and depends i suppose on what the draw up is protecting usually points infront of the next signal are just a form of speed control

[Harsig]

Apr 14, 2008 18:07:32 GMT Colin said:

Perhaps one for aetearlscourt or Tom........

I know that when a trainstop fails (obstruction or loss of air), it not only causes a dual aspect but also the signal in rear to remain at danger too.

So far, so so good.

Well not so good. You are confusing two different types of train stop failure here. The first type (obstruction under trainstop or loss of air) causes a dual aspect while the other sort (Trainstop failed down or trainstop head broken off ) causes the signal and signals a braking distance to the rear to remain at danger.

So let's take an example: station starter trainstop fails causing the home(s) to remain at danger.................what if there was a draw-up associated with the starter; would that also remain at danger, or would it carry on operating as it normally would (ie, because it can draw trains up slowly)?

Well I would expect all signals in rear of the signal concerned to remain at danger out to the braking distance. In practice this is often achieved by causing the track circuit immediatly in advance of the signal to fail, and this being in the overlap causes the signals in rear to remain at danger as well.
To take an example, if the trainstop on signal OP29 at Edgware Road were to fail down after a train departs eastbound then this would cause BP track to fail down (and also BQ) and since BP track is required clear for OP290, the draw up, to clear then this also fails. (As it happens this failure would also cause BQ track to fail down but this is just a quirk of Edgware Road being such a tight and compact site)

[Colin]

Sorry Harsig, I got so excited about asking the question that I tied myself up in knots there ;D ;D ;D

I was indeed referring to a trainstop failing down, with the signal behind also held at danger as a result.

Your example (OP29 & OP290) answers my question perfectly - my trainer at Ashfield House said "I'll look into that and get you an answer, but I suspect our answer (the service control group of trainers) is that the draw-up would act normally". He followed that up with "only a Technical Officer could answer that for sure" - I told him not to worry, I'd find out from a "premier information source"!! ;D ;D

Cheers

[suncloud]

Ok, how would the signalling know the trainstop head is broken off? I can understand there being a check mechanism to make sure it's up when it's meant to be and down when it's meant to be...

[mrfs42]

Swept path by the trainstop arm coupled with a calculated balancing spring [1] IIRC. [2]

Contacts being made/broken at specified angles/angular displacement.

[1] balanced against the mass of the trainstop head.

[2] though I may be talking utter faff here. That's how I'd design it anyhow.

[Deleted]

to pick up the track relay of the replacing track you need to feeds one comes from the track itself know has the R side and energises one coil the other comes from trainstop via 1's contact which is know as the Q side which energises the other coil thus picking the relay up (energising it) now that track relay a contact of that is in the selection for the signal behind also if home signals are involved maybe the one behind that aswell so if the head was in the fully ON postion 1's contact would not make so the TR (track relay) would never pick up thus keeping the signal behind and atleast one good trainstop in full working order

[railtechnician]

The trainstop has a contact neutralising spring and in the event of the head being broken off it will break all five contacts which will put the replacing track down causing the associated signal and the signal in rear to be maintained at danger as well as any repeating signal.

[Harsig]

Apr 20, 2008 7:02:11 GMT railtechnician said:

The trainstop has a contact neutralising spring and in the event of the head being broken off it will break all five contacts which will put the replacing track down causing the associated signal and the signal in rear to be maintained at danger as well as any repeating signal.

Surely in and of itself the breaking of all the contacts in the trainstop cannot put the replacing track down if the latter happens to be up at the time the defect occurs. Rather, once the track is down for other reasons (ie passage of a train) it subsequently remains down when those reasons no longer apply. This is implied by the phrasing of the second part of your post which talks about signals being maintained at danger, but nothing about them being put to danger, as would occurr with a 'spontaneous' track failure.

[Deleted]

the sudden failure of the head wouldnt cause the track just to drop as the trainstop is only there to pick the relay up once its up its held up with its own contact but when the track relay drops after the passage of a train it would never pick up again until the contact of the trainstop was finally made

[stanmorek]

Questions dear sirs. How much does a trainstop weigh (I would estimate 30-40 kgs) and are spares held anywhere for emergencies? There is a nice shiny one at Barbican on the eastbound platform. It looks either new or overhauled or do you paint them? Also are there are oil filled trainstops? Someone I was working with insisted there were some around the system and were fed by a tank off track though I've never seen one before.

[Deleted]

well it takes 4 people to lift one but on the exact weight i cant remember

the ERU (emergency response unit) keeps spare trainstops in there stores if one fails or requires changing urgently

westinghouse do make them new but they come with different connectors (well they still did in 1999) but 99.9 times out of 100 they are all overhauled at the REW acton we paint the heads every now and again

there is oil filled trainstops but they have there own tank or sump whatever you wanna call it these are called type J (outside and sub surface) and type K (tunnels) the other types we have to oil/grease on a 6 week basis are HO (outside) and HT (tunnels)

there is no massive tank beside the track for them the only thing i think of but these have all disappeared are the old style point heaters which were nicked named chip pans as they used insulating oil heated by the traction current then by pipes fed to the rail chairs around the points to heat up the stock and switch rail

nearly forgot we do have emergency trainstops but these are just the arm on a bracket with no electrical contacts i have only ever seen them use one once about 5 years ago at south ken

[stanmorek]

Ta. If we worked on the premise that 25kg is the maximum for manual handling regulations then I'd guess 70kgs for comfort. I have a set of trainstop diagrams somewhere...

[Deleted]

plus they are very awkward

[railtechnician]

As someone who changed many a trainstop, sometimes as many as three in a shift, let me add a comment or two.

aetearlscourt has said most of what I would say. He mentions the various standard trainstops in use today as the HO,HT,J & K. As he says the latter two are self oiling, this means that the oil is mechanically pumped around inside the trainstop from a sump within it as an auxilliary action of the normal operation of the trainstop.
All trainstops are regularly maintained whether they are 'self oilers' or not as they all have oiling points, there is also the matter of vibration and rail wear, rerailing etc which will or may put a trainstop out of gauge in more ways than most would consider at first glance. So they are gauged and the lid has to come off to check the correct operation of the contacts and the security of the electrical connections.

There are other trainstops, the central line used to have modified K types called KCs but the trainstop was the same with a bracket fixing instead of two of the four feet to fit the reduced size tunnels. On the Picc there are modified J types between Hatton Cross and Heathrow, yes an outside type used in cut and cover tunnel with two feet cut off to accommodate fixing next to F/B rail. I believe the JLE has some modified types too from what I used to see in the stores but having never worked on it I can't say any more than that.

Again as aetearlscourt suggests the only lineside oiltanks were contained below track level beneath the point heater consoles which were basically pump cabinets pumping hot sticky and smelly oil through the special rail chairs linked with hoses and jubilee clips. The oil itself smelled rather fishy and stuck like napalm to the skin, very nasty stuff indeed especially when having to work on the submerged pump in the oil sump.

As for handling trainstops I can't recall the weight but in fact even when four people are carrying one it still breaches all the handling guidelines because a trainstop is an irregular shape and has an irregular weight distribution such that with the HT and K types most of the weight is at the head end, especially since the replacement of the old Midland motor with the new and lighter aluminium type, and in the HO and J types it is on the side where the head is and biassed towards one end. The trainstop is officially carried on four hooks but finding four identical hooks can be a challenge. Also to do the job properly would require four identical individuals in terms of relative height and arm length. Invariably when four people carry a trainstop most of the weight is taken by two or sometimes one individual! There is nothing comfortable about lugging a trainstop but it goes with the job as most of the kit is similarly difficult to transport though in many ways it is far easier today than when I began on Signals in 1977.

As for the contact netralising spring, one would normally expect the track to be down when the head is knocked off unless someone has swung a sledgehammer at it, so it can't pick up when the track is unoccupied following the passage of a train. If by failure all the contacts have broken while the track is up then it will remain up until the passage of the next train when the track will fail down. The point is that regardless it fails safe.

[railtechnician]

I forgot to mention that tanks are sometimes seen trackside, generally near IMRs where they still exist. However, they are not oil tanks but air tanks, reservoirs at one time for the compressed air supply to the interlocking machine and programme machines. I believe there is still one to be seen outside the west end of Northfields IMR unless it has been removed in recent years.

As for trainstop spares there is an emergency store and there are ERU stores but there are a limited number of spares. I recall one Sunday night a few years ago changing five trainstops between Boston Manor and Northfields after a LC decided to send a defective train to the depot via Northfields to avoid 'setting back' and using the Boston Manor route. In the event five trainstops were decapitated and/or severely damaged, indeed one was lifted in three parts!

ERU delivered five replacements and we held up passengers as we commandeered the first car of the last but one or two trains to deliver them directly to each of the five locations. I think we had all five replaced by 0200 but ERU told us not to break any more as we had cleared available stock at the time. In a real emergency I'm sure we would've found a couple more, the old dodge was to 'borrow' from the training school! No doubt REW would've have had some almost ready for stores stock too as a last resort.

Most often I used to collect my own trainstops in an emergency as I was based 5 minutes from the emergency stores but for routine change purposes they were always delivered to site by ERU. Most mornings there would be at least half a dozen trainstops at the REW 'cage' which had been removed on routine and emergency jobs. The throughput must be on average around 30 or so a week of all types on all lines.

[Tom]

Apr 23, 2008 13:48:25 GMT railtechnician said:

On the Picc there are modified J types between Hatton Cross and Heathrow, yes an outside type used in cut and cover tunnel with two feet cut off to accommodate fixing next to F/B rail. I believe the JLE has some modified types too from what I used to see in the stores but having never worked on it I can't say any more than that.

The JLE uses HO types, but with a litton connector rather than the flipper.

Are the modified J types between Hatton X and Heathrow the ones referred to in the Emergency Stores book as a 'Heathrow' trainstop?

[mrfs42]

As far as I know the modified 'J's are indeed referred to as 'Heathrow' ones; although I've never seen a copy of the emergency stores one - I've got a note in with the file on trainstops.

What is the modification by the way - is it something to do with inductive spark quenching on the contacts?

[Deleted]

tom when i was finishing my apprenticeship in 1998 we were putting trainstops down around SMD on the JLE but taking out the litton plugs and replacing them with the standard snake these trainstops came brand new from westinghouse

[Deleted]

times have changed mr railtech since using 4 hooks we use straps like they have on curtain lorrys now for lifting them due to a incident where someone nearly lost there finger at rayners lane about 2 years ago but hooks are deffo easier and remain the norm pratice still but abit unoffical these days

[railtechnician]

Apr 23, 2008 19:25:23 GMT Tom said:

Apr 23, 2008 13:48:25 GMT railtechnician said:

On the Picc there are modified J types between Hatton Cross and Heathrow, yes an outside type used in cut and cover tunnel with two feet cut off to accommodate fixing next to F/B rail. I believe the JLE has some modified types too from what I used to see in the stores but having never worked on it I can't say any more than that.

The JLE uses HO types, but with a litton connector rather than the flipper.

Are the modified J types between Hatton X and Heathrow the ones referred to in the Emergency Stores book as a 'Heathrow' trainstop?

Yep I would imagine so, I don't know why they didn't give them a designation of their own but I suppose as there are only a few of them it wasn't warranted. On the maintenance modules they just used to show up as 'J-modified'.

Now you mention it I do recall the trainstops with litton connectors although I never looked too closely at them. I also recall the EP valves mounted on white plates for the JLE too.

[railtechnician]

Apr 23, 2008 20:43:32 GMT @aetearlscourt said:

times have changed mr railtech since using 4 hooks we use straps like they have on curtain lorrys now for lifting them due to a incident where someone nearly lost there finger at rayners lane about 2 years ago but hooks are deffo easier and remain the norm pratice still but abit unoffical these days

I think they had to! We had two sets of hooks at Acton and finding four the same length was a challenge. In the end we used to move trainstops on the single rail track trolley, from the van into the station as well as along the track but we had some hairy moments with that as we used to pile the tools on top too. An outrigger for the single rail trolley would've been a good idea but we didn't have one!

As for incidents one of the sparks that used to work with me did his back in and got retired as a result of a trip on the platform at Sudbury Hill. Webbing would've made no difference to that at all.

Funnily enough I was using webbing to move things like equipment cubicles way back in the 1980s. I was taught to properly lift, carry and shift all sorts of equipment in my days as a telephone engineer with the Post Office in the early 1970s and we were using webbing and other aids then. When I moved to LT in 1977 I found it an extremely backward environment in H&S terms.

[Deleted]

well it took them till around 1997-1998 to start using cembres (petrol drilling machines) instead of the fun hand bikes (manual chain driven drill) which are still used if the machine packs up

[railtechnician]

Apr 24, 2008 17:29:32 GMT @aetearlscourt said:

well it took them till around 1997-1998 to start using cembres (petrol drilling machines) instead of the fun hand bikes (manual chain driven drill) which are still used if the machine packs up

It was later than that on the Picc, we were using 24v battery bikes at acton but my King's Cross colleagues still used the old original black hand driven chain bike which really was hard work. In the old days the bonders used to drill as many or more holes with those than most techs would today with battery, 110v, petrol or diesel bikes! Then there was the ratchet and cramp for holes bigger than 3/8 !

[Deleted]

o yes remember them well doing stretcher bars

[Tom]

I remember using a ratchet and cramp on my points course, where they decided my muscles needed building up and I ended up drilling most of the holes myself! Thankfully I never had to use one in anger.