We made use of today’s rather wet and miserable weather to tend to a few odd jobs.
The first being the final jacking and tamping of the new sleepers on Muckleford Creek Bridge, now that the ballast wasn’t quite so wet, it had actually settled down very nicely on its own, but we perfectly a few minor little bits we just didn’t get time for a few weeks ago.
We then installed timber wedges besides the runners as required at the UP end of the Bridge, to help compensate for the deck movement we undertook a few weeks back, the wedges are simply to take up the slack and stop it wandering back over time.
The rest of the day was more or less spent fixing a geometry fault that was developing near this turnout at Muckleford, this one is due to embankment settlement, given how wet this year is (on top of last year’s wet year), it’s likely we’ll be attending to many of these settlement faults in the coming months.
Anyway, the end result is a much improved piece of track, which should also ride much better.
Thursday and Friday are nominally planned as inserting sleeper plates near Sawmill Rd, however, the weather is not looking at all kind, with a decent amount of rain forecast for both days, so please check back here Wednesday night for details of Thursday.
Well, after the great success of Thursday’s decking efforts, Friday proved to be a damp affair, however we still managed to achieve our aims, albeit in the rain.
We managed to get everything fixed up, ballasted and roughly tamped (only roughly as we’ll need to re-pack this in a few weeks once the ballast has vibrated into all the voids below the sleepers.
We then proceeded to undertake a significant number of load tests of the new decking, with the only real outcome being it is at least as stable, if not more so than the timber decking adjacent to it!
We even sat a Y class on the deck for half an hour or so while we had a cuppa, with no notable movement present, which is pretty ideal! We will be monitoring the sag of decking between the beams, it’s only the weight of the ballast that causes that sag, but we may find in warmer weather that could exaggerate, however a very lightweight beam in the deck centre would remedy that issue entirely if it turns out to be so.
A keen eye might also notice the graffiti on the Y class… it was coincidently Will’s birthday on Friday, and the workshop boys decided that needed a level of public announcement.
This week will actually be a week of no civil activity, as both staff are taking leave and given how active the gangs have been in recent times, it seems like a good time to give everyone a week off to recover from the freezing cold. From Tuesday next week, things will return to usual however. A blog post will be made with details on Monday next week.
Muckleford Creek Bridge is certainly on the way to needing a new deck, which as I’m sure anyone can imagine is an enormous amount of timber at an enormous cost! Given the last decking has really only lasted 30 years (and the other bridges are hinting at a similar rate of decay), it’s time to seriously consider alternatives.
One such alternative that we’ve decided to trial is Recycled Plastic, and today was the day we took that trial from paper and put it into practice.
So we began by removing a short section of the old deck at the very down end of the Bridge, which is nice and low, straight and good easy access, important things when trial fitting the new deck.
The panels that we made up last week were then lifted onto the bridge, slewed under the rails from the side, only a small amount of rail jacking was required to achieve this.
We then simply continued that process two and half more times to get the rest of the deck in, which actually did end up being very easy, with very little to no manual input required. We’re looking for a solution that means we can do these sorts of works without having to do the work at heights, hence this method has proven to be very effective, with the construction taking place on the ground.
We expect it would look very noticeably different to the timber, however it’s not as different as we expected, it slightly narrower, due to the available length of plastic, however otherwise pretty much identical dimensions to the timber decking, so it’s not really a massive change.
The final appearance is probably a little too neat for a typical timber bridge, a bit too uniform.
We were extremely pleased with the ease and speed with which it was installed, it was a learning curve and no doubt we could speed up the process significantly if we need to.
We gave up when it looked like the rain was about to hit, however tomorrow is a day of finishing fastening up the sleepers (plastic also, as we do want to get a option which is essentially maintenance free going forward), ballasting, tamping and running a testing and commissioning train to verify the design as suitable.
There won’t be any issues structurally, as the rails are directly over the beams, so the decking serves no more purpose than just to contain ballast, and transfer the load straight down to the beams, any issues will be more if the modified design with no tie rods and through bolts is sufficient to prevent movement of the kerbs, which is really a thing that’ll take a few years to evaluate, but it’s an extremely easy fix if we find an issue – just add them.
Tomorrow’s crew will be meeting at Maldon at 8am, where we will need a few truck drivers (Mick.. if we get this), then at the Bridge from 8.30am.
VGR Civil Blog 