I wonder who first thought of calling it that.the vertical separation of the catenary and the contact wire at the supports (the encumbrance)
I wonder who first thought of calling it that.the vertical separation of the catenary and the contact wire at the supports (the encumbrance)
Nothing much, as per the planning drawing I linked in post #12. It is just described as a maintenance area.There's clearly a big area of that deck that isn't going to be used for the actual railway alignment, … anyone know what's planned to be put on there? I'd suggest a solar array, or otherwise wildflower meadow!
We discussed this earlier, @mr_jrt noted it in post #11. I believe from the pdf drawing there’s a new pier 20a to go in alongside the covered way, it’s in the side view but not visible in the plan view.At the top left of the last picture in #34 it looks as though there's going to have to be an area of supplementary deck to tie in to the approach. It's not yet clear how it will be supported.
Don't worry about that, the Buddleia will move in soon enough.There's clearly a big area of that deck that isn't going to be used for the actual railway alignment, … anyone know what's planned to be put on there? I'd suggest a solar array, or otherwise wildflower meadow!
Regardless of what the draft plan shows, the original Pier 24 is very much in existence and stands a few feet away from the north end of the box, in a suitable position for supporting the connection to the box. Pier 24 can be seen in both of the pictures above. The splaying out and dogleg of the block wall at the other end does not appear on the draft plan either.Ah yes, you can just see its corner in the plan view. Thank you.
They also got rid of dangerous support pillars in the 10 foot. They possibly no longer meet new build standards.It's an extremely substantial structure compared to the old viaduct. Seems like a bit of a waste of materials, but I guess a concrete box is easier to build than a curved bridge structure like the old one?
The extremely shallow angle that the EWR alignment crossed the WCML makes the positioning of intermediate piers almost impossible. The previous structure was highly bespoke in order to achieve this - which is ultimately part the reason it failed. The new structure is very heavy, very solid, very wasteful of material but (and here's the all important part) very low risk for the Structure RAM in the future - and by association the operation of the WCML in particular.Crikey, that's pretty hefty! What is the reason for going for such a large deck rather than a simple bridge the width of the formation?
Does RAM stand for Risk Assessment Method?very low risk for the Structure RAM in the future
Does RAM stand for Risk Assessment Method?
Fairly standard design now, a lot of skewed HS2 structures over motorways and rail will be like this.It's an extremely substantial structure compared to the old viaduct. Seems like a bit of a waste of materials, but I guess a concrete box is easier to build than a curved bridge structure like the old one?
I kind of feel sorry for the poor people in the houses backing on to the structure who now have a large concrete wall as their view.
Crikey, that's pretty hefty! What is the reason for going for such a large deck rather than a simple bridge the width of the formation?
Correct me if I'm wrong, but one reason for the 'box' design might be to reduce disruption to the main line during construction - a total of three days posession so far. I suspect that the original construction in the 1960s caused far more disruption, even with the low 'health and safety' precautions of the time. Another benefit could be to reduce the risk of a derailment on the EWR line toppling onto the mainline track.
The flyover south of Welwyn Garden City is similar:Worth noting that BR took a very similar approach for the Rugby grade separation back in the Sixties, although this is one track over three, with supports in the ten-foot, so much smaller.
There’s loads once you start looking for them, someone mentioned the new Heathrow flyover being unusually a girder bridge, but the old one is a box. Durnford Rd near Wimbledon is another older example.Worth noting that BR took a very similar approach for the Rugby grade separation back in the Sixties, although this is one track over three, with supports in the ten-foot, so much smaller.
I too am a little surprised, given the extent of work which went into producing a pretty bespoke curved viaduct for the Stockley Flyover. But it's good to see the progress at last.
Aren't there three Stockley flyovers? The original one, the new one immediately north of the old one, and the other new one a bit further east. Maybe the third has a different name. The first and third are box-type, as is the proposed flyover at Ravensthorpe on the Huddersfield-Westtown scheme.There’s loads once you start looking for them, someone mentioned the new Heathrow flyover being unusually a girder bridge, but the old one is a box. Durnford Rd near Wimbledon is another older example.