Very old wooden sleepers

[IanKR]

At certain sites on Southeastern - particularly at the x-over junction west of Lewisham and on the 'densely-pointed' approaches to London Victoria - I see what look like *very* old wooden sleepers. They are heavily ridged, cracked and gnarled, but they obviously still function.

While newly-laid track uses concrete sleepers, I assume that it is just too difficult to replace the wooden sleepers at these complex junctions with concrete ones, and that they just replace the track on top of them, as and when?

I'd expected them to replace the ones at Lewisham earlier this year (or was it late last year?) when they repaired the diamond crossing.

Just shows what a resilient building material wood is, I guess.

 

[The Snap]

At certain sites on Southeastern - particularly at the x-over junction west of Lewisham and on the 'densely-pointed' approaches to London Victoria - I see what look like *very* old wooden sleepers. They are heavily ridged, cracked and gnarled, but they obviously still function.

While newly-laid track uses concrete sleepers, I assume that it is just too difficult to replace the wooden sleepers at these complex junctions with concrete ones, and that they just replace the track on top of them, as and when?

I'd expected them to replace the ones at Lewisham earlier this year (or was it late last year?) when they repaired the diamond crossing.

Just shows what a resilient building material wood is, I guess.

P-way infrastructure on approaches to major stations or junctions often appears to be in bad condition. The simple reason is that it is so difficult to replace, with so few possessions available. Barring Christmas Day and Boxing Day, most major termini have next to no blocks all year round. I know at Piccadilly you get a couple of hours on a Saturday night, at best! To undertake major renewal of the infrastructure you need long blocks (54 hour or the like), which you simply don't get often enough.

 

[30907]

IIRC for many years it wasn't economical to produce concrete sleepers except for plain track, and I suspect it still isn't in the case of complex S&C such as Lewisham.

 

[swt_passenger]

IIRC for many years it wasn't economical to produce concrete sleepers except for plain track, and I suspect it still isn't in the case of complex S&C such as Lewisham.

They do now produce over length concrete sleepers for use with S&C such as crossovers, and in some cases they are joined between the two tracks with steel sleeves. Seems to be the way stuff is being manufactured for carriage on the tilting wagons.

As you say though, beyond a certain level of complexity perhaps timber sleepers are still useful. Especially if they are constrained by time and cannot replace an entire area in one go?

 

[Bald Rick]

*Pedantic hat on* Plain Line track has sleepers, Switches and Crossings have bearers.

Now I've got that out of my system...

Until relatively recently (15-20 years ago) S&C manufacturers were not able to produce concrete bearers with enough precision for the holes drilled for the base plates. With timber, if one was wrong - and they often were - the bearer was just turned over or round and new holes drilled on site. Not really sensible with reinforced concrete. However S&C bearer manufacture got much more reliable, 2 decades ago, such that concrete is now the standard. My S&C maintenance book from 1999 has very few examples of concrete layouts, but Euston Remodelling (2000) was done predominantly in concrete.

There was also a reluctance from the maintenance guys to have concrete bearers for related reasons - a broken / damaged timber bearer is easily dug / chopped out, new one put in from store (cut to length) holes drilled on site, base plates reinstated. With concrete, the new bearer has to be specially made to precisely the correct size with the base plates holes / fixings in precisely the correct location for the one it replaces. This can take some time to fabricate.

The foregoing was particularly the case when much of the S&C on the network is non standard, ie to a myriad of slightly different angles, curvature, etc.

However, now that most new S&C is to a small number of standard designs, there is a decent stock of most relevant bearers, and patterns for many others on the shelf, so replacements are easier to source. As an example, the old London Bridge had scores of non-standard S&C units, when finished, the new one will have only 3 IIRC.

Re Lewisham. It's non-standard. And a pig to maintain, principally because there are very few hours in the year when there are no trains across it. The rails and ironwork is being renewed in the next year or so, and selective sleepers I gather, but what it really needs is to be completely dug up and relaid. But that would take the best part of a week (more if it was slabbed) and realistically that's not going to happen if it can 'make do and mend' for a while longer. The junction itself is actually pretty reliable.

 

[DarloRich]

*Pedantic hat on* Plain Line track has sleepers, Switches and Crossings have bearers.

I was gong to say that!

You should see some of the prefabricated S&C layouts being put together. Lego on an industrial scale!

 

[Trog]

*Pedantic hat on* Plain Line track has sleepers, Switches and Crossings have bearers.

Except for those that have timbers.

Also concrete bearer turnouts are older than people think, the first ones were installed in the late 1970's early 1980's. Although there was then a long wait until they started to be come more common.

You do sometimes find old timbers in siding S&C until about ten years ago there were still a few LNWR vintage sleepers in the sidings at Wolverton. Huge great things made out of what I think may have been pitch pine, I have been told that on removal the core of the timber was still sound, smelled strongly of creosote and was still larger than a modern timber is when new.

 

[IanKR]

Love this board. Thanks for your replies, guys. Especially to Bald Rick.

 

[swt_passenger]

*Pedantic hat on* Plain Line track has sleepers, Switches and Crossings have bearers.

Educated. But in my defence I was just following on from the previous post!

 

[hwl]

GWR wooden sleeper manufacturing video:

https://www.youtube.com/watch?v=0RlD0w-JbUQ

Autoclave creosoteing, multi head drills

 

[R4_GRN]

Ouch, no Health and Safety equipment worn or supplied I suppose, bowler hats, collar attached shirts with no collar and probably light footwear makes the hair on the back of my neck stand up.

 

[321446]

I would like to add my thanks for a thought provoking question and superbly detailed but clear answers. I mearly drive across the things but it had occurred to me that there must've been a complicated answer why things were so!!

As an aside, apart from a few crossovers, reasons why covered above, would there be any deep reason why the down platform at Billericay is probably the only part of my route I've notice still laid with wood sleepers. The up Plt is concrete. Just a small thing that gets me on occasion.

 

[Trog]

The main reason for using timber sleepers new these days, is where the ballast is very shallow, perhaps on under bridges etc. Longer lengths are usually older track that has yet to be relayed in concrete or steel.

As for the dangers of creosoting sleepers, before creosote a process called Kyanising where the sleepers were soaked in a solution of corrosive sublimate of mercury was used. I bet that did not do the workers much good either.