Clamp Locks

[beast66606]

Whilst awaiting for an early morning gypsum train I took some shots of the clamp locks at Helsby which I thought might be of interest.

 

[Pugsley]

Thanks Dave, most useful B) B)

[Western Star]

For those of us who might be stuck in the "Vertical Tappet" and "Straight Switch" time discontinuum... what moves the switch tongues? what is the function of a clamp lock? what is bolted to the running face of the switch toe?

 

Thank you for such interesting images, Graham

[beast66606]

The little grey box is the power pack.

 

The crank is a back drive to ensure gauge through the switch.

 

Each yellow box contains a pump motor which drives the blades over, valves control the actions, so basically the left hand unit would drive the blades the way they are positioned in the photo, when the blades needs to be reversed the right hand unit drives, the valve on the left is open which allows the fluid to return to the reservoir and the blades move.

 

It's slightly more complicated due to detection etc. but in essence thats what happens.

 

The first few seconds of this video show the same points in action.

 

http://www.youtube.com/watch?v=u2pAW2zKZJM

 

 

hth

[43110andyb]

For those of us who might be stuck in the "Vertical Tappet" and "Straight Switch" time discontinuum... what moves the switch tongues? what is the function of a clamp lock? what is bolted to the running face of the switch toe?

 

Thank you for such interesting images, Graham

 

 

The movement comes from the hydraulic actuators (grey in colour) in the 4ft. Driven from the power pack as Beast has mentioned. The power pack however is the large grey unit on the right of the points with the hydraulic hoses leading to the actuators. The yellow covers hide the microswitches that detect the position of the points both in the open and closed positions of the switch rail. The clamp that locks the points is housed on the brackets that are fitted to both switch rails. when the points complete thier travel the clamp (or claw) is forced behind the stock rail and into the bottom of the yellow box (clamp lock body) and locks it.

[Re6/6]

Thanks for those very useful pics Dave. I've been looking forward to the Colin Craig 4mm versions, but they're on hold ATM since Colin has been unwell. These shots will be a good aid to building some clamplock mechs.

[Will Vale]

Great pictures, thanks! It's always interesting to see how wide the variety of fittings (and colour and texture) there is in such a small area.

[P.C.M]

Thanks Dave,

Those pics are very useful, and will help me get some dimensions. From other pics I have seen it looks like the power packs vary a bit.

 

Cheers Peter.

[Guest jim s-w]

Hi All

 

This is how Colin's version looks - He includes 2 types of power packs, this is the smaller one

 

 

HTH

 

Jim

[Merfyn Jones]

Hi All

 

This is how Colin's version looks - He includes 2 types of power packs, this is the smaller one

 

HTH

 

Jim

 

Further to Jim's picture above and Dave's shots at Helsby, I can confirm that the power packs at Llandudno Jct. and Llandudno are all of this type/size.

Merf.

[P.C.M]

Further to Jim's picture above and Dave's shots at Helsby, I can confirm that the power packs at Llandudno Jct. and Llandudno are all of this type/size.

Merf.

 

 

Hi Merfyn,

I think I will try and do some of them then.

 

Cheers Peter.

[The Stationmaster]

If you really want to know just about everything there is to know about clamp locks wind up google and type in 'rail clamp point locks'. Pretty near the head of the list you will find a link to an RSSB Code of Practice document GK/RC0774, Rail Clamp Point Locks - containing descriptions, drawings and explanations of how they work plus the necessary drawings to show how they are installed on various patterns of switches (e.g a double slip) etc.

 

Well worth a look if you are interested.

[Oldddudders]

Not sure it's been mentioned, but under failure conditions, clamplocks are "pumped" by hand, rather than "wound" as would be the case with conventional electric motorised points. It's a bit like using a trolley jack under your car, with a lever that is placed in a tube in the pump housing - you just pump back and forth and it all happens. What I can't remember is whether the pump handle itself is detected - i.e. on removal of the pump handle from its storage cabinet the electric power to the pump is disconnected, as I think is often the case with electric points.

[PaulRhB]

you just pump back and forth and it all happens. What I can't remember is whether the pump handle itself is detected - i.e. on removal of the pump handle from its storage cabinet the electric power to the pump is disconnected, as I think is often the case with electric points.

The clamplocks are manually moved by opening the box next to the point and with permission from the signalman turning a switch to hand. You then insert the handle (kept in the point cabinet with the clips etc) and while holding a small lever to Normal or reverse pump them over until the blades and the ram have stopped. You then have to scotch and clip the points for facing moves or just scotch for trailing. Much prefer clamplocks to winders.

 

Different locks protect the point controls and the equipment cabinets just to be safe and you have to ask the Signalbox first or you could get a very nasty surprise when trying to take them on hand.

[The Stationmaster]

Clamp locks can be quite nasty things to hand pump and are definitely a 'keep your hands well away' job. The pumping bit is fairly easy - it's why the switches can do you have to watch.

 

All is explained in the link I suggested above - it also includes an explanation of hand operation, well worth a look if you're at all interested.

[Craig Watson]

Hmmm, manual operation of power points, a big part of my day to day job!

 

I find clamplocks the easiest to work manually, with HW you have to clear the ballast away to save skinning your knuckes while winding!

 

With HW the insertion of the handle into the machine operates a switch which cuts off the power, when finished you have to pop the button back in to restore control to the signalman, with Clamplock you turn the switch from "power" to "manual" with the permission of the signalman, hold the small lever to either normal or reverse then pump away, the controls being under the lid of the "power pack".

 

Point machine covers have 2 padlocks, a 221 S&T one and a 222 operations one, a 221 key will open both but a 222 key wont open a 221 padlock which prevents ordinary points operators gaining access to the "gubbins" of the various machines.

 

The saltire symbol on the power pack has an S&T meaning too, I think it possibly denotes that the machine is self bleeding but may be 100% wrong.

 

HPSA ones use the same handle as HW but are a completely different animal which require some manual dexterity skills to operate (unless you're trusted enough to have a 221 S&T key to take the cover off ), luckily (for me anyway) they seem to be the most reliable we have

 

I'm currently training my replacement on the practical side of all of the above prior to my move back into the signalling centre, I'll grab some pics next time we're out.

 

Cheers

 

Craig

[Craig Watson]

The clamplocks are manually moved by opening the box next to the point and with permission from the signalman turning a switch to hand. You then insert the handle (kept in the point cabinet with the clips etc) and while holding a small lever to Normal or reverse pump them over until the blades and the ram have stopped. You then have to scotch and clip the points for facing moves or just scotch for trailing. Much prefer clamplocks to winders.

 

Different locks protect the point controls and the equipment cabinets just to be safe and you have to ask the Signalbox first or you could get a very nasty surprise when trying to take them on hand.

 

If your lucky enough to open a cabinet with a handle in it! (we keep handles in the van just in case )

 

There are exceptions to clipping (or clamping as we call it north of the border!) and scotching, if the signaller gains detection once the points have been operated they will move the respective thumbswitch on their panel to the required position and ask us to restore them to power, they then use the interlocking as normal to signal the train.

 

Cheers

 

Craig

[PaulRhB]

Yep we've removed the handles from a lot of the points cabinets due to contractors nicking them for personal kit. We tried spraying them bright pink first but that didn't stop it. Our MOMs, S&T and Pway carry them as van kit now except in a few remote locations where they rarely use points in possessions. If we go out it helps to remember to take the handle!

We only have two Top winders left on the area the rest are clamplocks.

 

The nasty surprise I refered too was people forgetting to take them on hand before clipping, the handle is very useful for knocking in and out scotches while keeping fingers safe.

[Craig Watson]

Yep we've removed the handles from a lot of the points cabinets due to contractors nicking them for personal kit. We tried spraying them bright pink first but that didn't stop it. Our MOMs, S&T and Pway carry them as van kit now except in a few remote locations where they rarely use points in possessions. If we go out it helps to remember to take the handle!

We only have two Top winders left on the area the rest are clamplocks.

 

The nasty surprise I refered too was people forgetting to take them on hand before clipping, the handle is very useful for knocking in and out scotches while keeping fingers safe.

 

We re stocked our cabinets about 6 or 7 years ago with new clips and handles, all sprayed luminous green, most have disappeared over the years, it's funny going out to big engineering jobs and seeing private contractors using the still green clips, we've got a few back that way, If we have a big renewal around a junction area we now go out the day before and strip the place bare, especially if they're fitting shallow depth replacements as new yellow clips are supplied with the job, inevitably if we don't they disappear, at £40ish a clip it doesn't take long for the cost to mount up.

 

We've no top winders, just HW and HPSS/HPSA where the handles go in horizontally.

 

I had my trainee with me at a points failure a few days ago, one of the things I emphasised was to use the handle to knock the scotch out as it's what I was taught years ago, never put your hand between the blade and stock rail!

 

Cheers

 

Craig

[PaulRhB]

Here's a good link to all sorts of old railway training films,http://www.railnetchannel.tv

 

Point winding

http://www.railnetchannel.tv/avc-view.aspx?videoid=30&categoryid=5

 

 

 

[43110andyb]

The saltire symbol on the power pack has an S&T meaning too, I think it possibly denotes that the machine is self bleeding but may be 100% wrong.

 

 

Craig

 

 

You are correct . The pump unit is fitted with a snorkle valve for self bleeding in the event of an air lock.

[Foulounoux]

My day job is European warranty manager for a major hydraulics company

 

What I now realise is that with a bit if ingenuity I could replicate the solenoid v slow action model point motors in real life

 

For the slow motion motors using the current technology as described above

For the peco/seep solenoid effect we do what is colloquially called a bang bang valve.

 

 

Hat coat .....

 

Colin

[Oncomin5torm]

To dredge up an old topic, when did clamp lock motors come into use on the BR network?

I cannot find any info of this, I have seen videos of Penmaenmawr on the welsh coast in 1995 with them, but was it much earlier than this?

Thanks in advance
Alex

[Grizz]

Hydraulic clamp locks, pretty reliable as long as the ironwork isn’t hanging and timbers voiding. The rams were a bit of a git to change but once in and done, no probs. The yellow covers were originally light grey and had the BR logo embossed in them. Occasionally the hoses were extra long because the pump unit was in the opposite cess due to limited clearances. 

Totally agree that they are way easier when taking them on manual to pump across, compared with the loss of knuckle skin when winding point handles.
 

Once saw a PWAY contractor start up a rail saw and accidentally cut straight through two sets of hydraulic hoses on two sets of points at Camden East Jcn just going into the evening peak.
Hydraulic fluid everywhere and the jcn route locked for ages with everything at a stand. Mobiles going off everywhere, even the odd SPT ringing occasionally.... Lots of rude words......

Good job we always carried loads of spare hoses and fluid on the van. Got a massive thanks from the M.O.M. for sorting out someone else’s cluster feck and got an O.T. shift out of it as I recall. 

Happy Days......

[Pandora]

On 03/07/2010 at 19:17, PaulRhB said:

The clamplocks are manually moved by opening the box next to the point and with permission from the signalman turning a switch to hand. You then insert the handle (kept in the point cabinet with the clips etc) and while holding a small lever to Normal or reverse pump them over until the blades and the ram have stopped. You then have to scotch and clip the points for facing moves or just scotch for trailing. Much prefer clamplocks to winders.

 

Different locks protect the point controls and the equipment cabinets just to be safe and you have to ask the Signalbox first or you could get a very nasty surprise when trying to take them on hand.

When hand pumping, there is a  spring-loaded lever just under the cover to operate a  divert valve,  the divert valve  sel;ects either the handpump or the electricpump as the source for the hydraulic rams.

The rams are attached to the lambchop bracket bolted up in the fourfoot and there is the A bar which is custom drilled on site by S&T.

Clamp locks are not popular with S&T and Tamper crews,  rumours of there demise of clamplocks for HW electromechanical  point machines have been rife for 30 years, yet still they are installed.