Lifting signals

[MDickinson]

Im in two minds over an upcoming job.. We have to lift out and move an existing BRWR two arm bracket signal, and would like to find out how other preserved railways do it.
The question is.. is it best to lift the signal out in one piece, or unbolt and lift off the girder bracket and two dolls, then lift out the main post? The signal in question is not some massive long bracket affair, just the usual type with the two dolls about 6ft apart.
I was told that many years ago when the signal was installed, the main post was put in the ground and then the bracket with dolls on was lifted and fitted in place. I have thought that doing it that way could be dangerous, as the bracket would have to be hanging from the crane and swinging about etc whilst being fixed to the main post. Not to mention how the person doing up the bolts is going to get up there to tighten them with all this going on!
Also, anyone got an idea of the weight of such a signal? Can't be more than a couple of tons surely..

Mike.

[ferroequine]

The optimum way to lift them is with the bracket attached - provided you have a big enough crane that can take the load - DON'T FORGET THE CONCRETE at the bottom of the main post! That is how they often seem to have been erected, presumably because it was easier to put the main components together on the ground (which it is).

Dismantling can turn out to be very awkward and time consuming (bitter experience speaking there) but it might be sensible to remove such things as lamp cases and the enamelled arms to avoid the risk of damaging them.

PS I'm not sure of the weights but the concrete will add somewhere between 1 and 2 tons and as the post comes out of the ground you need to watch out for corrosion on the bolts securing the concrete sections and on the post where it goes into the concrete - not so much checking for where you will go with the wire brush but keeping an eye to make sure things don't start parting company.

PPS You also need to be careful about where you are replanting the signal making sure it is going into decent ground. With one where I had some involvement we had so much trouble getting the ground - basically ash and not much else - to hold it securely that in the end the bottom of the hole was treated to a foot of reinforced concrete and the concrete section on the bottom of the main post was sat on that before the hole was backfilled. And when backfilling make sure you tamp down as you go - according to an old Worcester Lineman it's 'fill 6 inches and thump', which seemed to work very well when we shifted a straight post signal (without a crane).

[MDickinson]

[i]The optimum way to lift them is with the bracket attached - provided you have a big enough crane that can take the load - DON'T FORGET THE CONCRETE at the bottom of the main post! That is how they often seem to have been erected, presumably because it was easier to put the main components together on the ground (which it is).

Dismantling can turn out to be very awkward and time consuming (bitter experience speaking there) but it might be sensible to remove such things as lamp cases and the enamelled arms to avoid the risk of damaging them.

I do intend to remove the arms, lamps, and as many castings as we can before lifting the signal out, as well as the ladder. I've seen ladders bent into all sorts of strange shapes because they have not been taken care of.

Speaking to our crane crew, they have suggested using a 'choke' strap around the main post rather than lifting off the bracket, in case the bracket starts moving up and the posts stays where it is!

PS I'm not sure of the weights but the concrete will add somewhere between 1 and 2 tons and as the post comes out of the ground you need to watch out for corrosion on the bolts securing the concrete sections and on the post where it goes into the concrete - not so much checking for where you will go with the wire brush but keeping an eye to make sure things don't start parting company.

This is where things get interesting.. I have been told that when the signal went in many years ago, there were none of the proper concrete 'half' sections avaliable, so a 45 gallon drum filled with concrete was used! We do now have the proper concretes avaliable so I would like to change them over if possible, the signal is going to be laid flat on a level piece of ground to be cleaned up and re-painted before re-installation.

Mike.

[Mike Hodgson]

If you know it's a 45-gallon drum of concrete, surely you should be able to calculate the weights?

[David Holden]

A gallon of water weighs 8.336 pounds.
45 gallons of water weighs 375 pounds.

Specific gravity of water 1.0, specific gravity of concrete 2.2

45 gallon drum full of concrete 825 pounds, around about 7.4 cwt.

Usual disclaimer for maths this time of night!

[ferroequine]

I do intend to remove the arms, lamps, and as many castings as we can before lifting the signal out, as well as the ladder. I've seen ladders bent into all sorts of strange shapes because they have not been taken care of.

Speaking to our crane crew, they have suggested using a 'choke' strap around the main post rather than lifting off the bracket, in case the bracket starts moving up and the posts stays where it is!
Mike.

I think they are very sensible not to lift by means of the bracket - sometimes they are a devil to get apart but occasionally they come off the post very easily and you might have one of those!

Sensible idea to strip as much as possible, especially ladders, they bend a bit too easily.

[Steve]

Mike,
No-one has pointed this out yet, so....

In case you're not aware, the bracket on a WR tubular is not simply clamped onto the main post. Two of the shaped castings (the upper pair I think) which appear to clamp round the post actually have a stud protruding into a locating hole drilled in the post. So loosening off and lifting doesn't work.

To get the bracket off therefore requires that you separate the front and back trusses of the bracket by an inch or two. Since this requires that everything which links the two trusses (end plates, plates under dolls, x links, platform supports...) be unbolted at least from one of them, and since some of those bolts will be seized/corroded, doing this in mid-air is not likely to be easy!

Conclusion: as others have said, strip the small stuff then lift the bracket and post as a unit if your crane can. If not possible I suggest you need some proper access equipment to dismantle it in the air: scaffolding or a hydraulic access platform etc. if you can.

SJG

[MDickinson]

Mike,
No-one has pointed this out yet, so....

In case you're not aware, the bracket on a WR tubular is not simply clamped onto the main post. Two of the shaped castings (the upper pair I think) which appear to clamp round the post actually have a stud protruding into a locating hole drilled in the post. So loosening off and lifting doesn't work.

To get the bracket off therefore requires that you separate the front and back trusses of the bracket by an inch or two. Since this requires that everything which links the two trusses (end plates, plates under dolls, x links, platform supports...) be unbolted at least from one of them, and since some of those bolts will be seized/corroded, doing this in mid-air is not likely to be easy!

Conclusion: as others have said, strip the small stuff then lift the bracket and post as a unit if your crane can. If not possible I suggest you need some proper access equipment to dismantle it in the air: scaffolding or a hydraulic access platform etc. if you can.

SJG

Thanks Steve! Very useful information there.
I was thinking that the bracket can't be simply clamped in place, seemed an awful lot of weight to carry otherwise. Would also seem to render the story I was told of putting the bracket on with the post up in the air during the original installation highly unlikely.

For completeness, here is the signal in question.


Mike.

[SignalboxCat]

There is an attachment for road-railers which is a "signalpost grab" works for tubular posts. 'Cat saw it being used to good effect in a possession on the mainline (sorry not a Heritage example) to remove disused (colour-light) signals. The "grab" fitted onto and held the post whilst it was unfastened from the base then is easy to lift/manoevre with the RRV (360 type) arm.

Brackets/gantries 'Cat has seen being removed (rail cranes/RRVs) on the main line were taken out in one piece (leave base behind) then cut up once on the ground (can use a MEWP RRV to chop them up in the air but chopping up on the ground easier provided your crane/RRV is meaty enough for the lift of the whole thing at the required radius).

As for installation; crane lifts post in; crane then holds bracket in place whilst man in MEWP fastens it on. Or crane lifts whole thing. Just remember to work out the CoG for the slinging. 'Cat has also seen a neat "necklace" attachment fabricated (and properly tested before use) for lifting bracket signals with tubular posts so as to get the load evenly slung.

[JG Morgan]

SAFETY ALERT!

A gallon of water weighs 8.336 pounds.
...
Usual disclaimer for maths this time of night!

The published maths is OK, but:
"A Pint of pure water weighs a pound and a quarter"
and http://hypertextbook.com/facts/1999/KatrinaJones.shtml gives the density of normal concrete as 2400 kg per cubic metre.
Therefore, to the reader in the UK, a gallon of water weighs 10 pounds.
A standard oil drum holds about 45 (imperial) gallons, so full of concrete weighs 1080 lbs, or 9.6 cwt.

[Steve]

We put one of these signals IN last year. Unlike taking it out, where I advocated lifting the baracket and post as one, it was done in sections.

The main post went in first, then the bracket was lifted as an assembly. Well two interlocked assemblies really....

The front and rear trusses were assembled on the ground with the linking fittings (mentioned above) bolted to one or the other, but with the trusses about 3" further apart than they should be. Extra long studding was put through the clamps. Timber baulks were inserted as spacers to hold the trusses apart. The various linking pieces were arranged such that the alignment between the two halves of the assembly was held.

This assemblage was then lifted using strops through both trusses (which of course held them together), and lowered over the post. When in position, the timber baulks were knocked out and the the two halves of the bracket came together and engaged the studs in the holes in the post, helped by nutting up the studding. The remaining bolts were inserted in the linking items. Done!

It was much simpler when seen in practice than it sounds here!

The longer part of the job was all the de-seizing and restoration work on the signal to make it useable in the first place. But that would be off topic.

SJG.