Cost of building a new railway bridge over an A road?

[CambrianView]

Hello Guys
I've read threads about the cost of building a road bridge over a railway, but not the other way round.

There are plans to reopen a single track branch line in my area, but this would involve building a bridge to carry the railway over the A5 trunk road. My understanding is it would be to carry a tram like shuttle service, so no freight.

Could anyone furnish me will a ball park figure for a single track railway bridge over a two way trunk road? Many thanks.

 

[LBMPSB]

Hello Guys
I've read threads about the cost of building a road bridge over a railway, but not the other way round.

There are plans to reopen a single track branch line in my area, but this would involve building a bridge to carry the railway over the A5 trunk road. My understanding is it would be to carry a tram like shuttle service, so no freight.

Could anyone furnish me will a ball park figure for a single track railway bridge over a two way trunk road? Many thanks.

The cost of a new road bridge that was to be built on the restored Northumberland rail line had risen from £11M estimated in 2021 to £30.6M by April 2023, as reported in the New Civil Engineer. Probably a lot higher now since inflation has been very high since April 2023. Costs will be higher for a railway over road since you need to add in the costs of deconstructing the Permananet Way and then rebuilding it, including cost of disruption to rail traffic. A lot of rail over road bridges are now constructed alongside beforehand and then slid into position to minimise the amountof time a railway is closed.

 

[Flying Phil]

The preserved Great Central Railway is at present "Bridging the Gap" between the two parts North and South of Loughborough. The first of seven sections was a new bridge across the Midland Main Line. This was constructed at the time 2018, as the MML was due to be electrified. There was a lot of co-operation with NR and I think the cost was around £3M(single track new abutments and deck). Then there has been a canal bridge refurbished @£1M(double track)2020, a new bridge deck across the A60 road(double track) @ £1M 2021 and the current fundraising is for a single track bridge section Factory Flyover, sections 3 and 4, cost expected to be @£3M, start this year. Finally it will need a 50m embankment and a 200m embankment to complete the job. There has been a lot of volunteer time involved in planning/design but detail design and construction has been contracted out.

 

[stuu]

The cost of a new road bridge that was to be built on the restored Northumberland rail line had risen from £11M estimated in 2021 to £30.6M by April 2023, as reported in the New Civil Engineer. Probably a lot higher now since inflation has been very high since April 2023. Costs will be higher for a railway over road since you need to add in the costs of deconstructing the Permananet Way and then rebuilding it, including cost of disruption to rail traffic. A lot of rail over road bridges are now constructed alongside beforehand and then slid into position to minimise the amountof time a railway is closed.

£30m for a single road bridge is insane. There must be something else included in that cost. The new bridge at Machynlleth opened yesterday cost £40m for an 800m long viaduct.

To find the cost of a railway bridge, find a recent road scheme which has built one, the consultation reports online will normally have estimates for the cost of structures

 

[Meerkat]

Costs will be higher for a railway over road

How long is a piece of string - cutting a bridge into a railway embankment will probably be cheaper than buying the land for and then building the ramps to get a road over a railway (ie to replace a LC).

 

[The exile]

£30m for a single road bridge is insane. There must be something else included in that cost. The new bridge at Machynlleth opened yesterday cost £40m for an 800m long viaduct.

To find the cost of a railway bridge, find a recent road scheme which has built one, the consultation reports online will normally have estimates for the cost of structures

The thing is that an awful lot of that cost will be the same whether it’s an 800m long viaduct or a single arch bridge over a narrow road.

 

[Ploughman]

Bridges over Roads will probably be costlier due to the increased length of the ramps either side.
Roads can better cope with the length of ramp required.

 

[Gloster]

Might there also be an additional cost of land acquisition as the approach embankment near the bridge would be wider than the existing railway property. I presume that the alternative would be expensive piling.

 

[stuu]

The thing is that an awful lot of that cost will be the same whether it’s an 800m long viaduct or a single arch bridge over a narrow road.

True, but a reopened railway will almost certainly need more than a single bridge. I assume the OP is talking about Oswestry, so a new station is needed as well, and possibly new infrastructure at Gobowen

 

[Llanigraham]

If this is indeed to build a new rail bridge over the A5 Oswestry by-pass on the line to Gobowen then it will certainly not be a simple operation. Currently this is a level crossing so any rail bridge is going to require some long embankments on either side of the new bridge to allow sufficient road clearance height and this would require considerable land purchase either side of the road.

 

[snowball]

If this is indeed to build a new rail bridge over the A5 Oswestry by-pass on the line to Gobowen then it will certainly not be a simple operation. Currently this is a level crossing so any rail bridge is going to require some long embankments on either side of the new bridge to allow sufficient road clearance height and this would require considerable land purchase either side of the road.

Unless the road was diverted to pass over the line adjacent to the level crossing.

 

[Llanigraham]

Unless the road was diverted to pass over the line adjacent to the level crossing.

Unfortunately the proximity to the roundabout to the north makes that most unlikely.
And probably just as expensive.

 

[swt_passenger]

£30m for a single road bridge is insane. There must be something else included in that cost. The new bridge at Machynlleth opened yesterday cost £40m for an 800m long viaduct.

I was trying to find any details of this matter in the Northumberland Line thread. I don’t think it was ever clear exactly what the extra costs were for. I did wonder if the headline figure included all the rail work at Newsham including the station, the track redoubling southward, and the level crossing closure. Nonetheless it still seemed a relatively huge increase…

 

[snowball]

The A5 is a trunk road for which National Highways (formerly Highways England, formerly the Highways Agency) is responsible. Whilst I don't think there are any current plans to alter the A5, they might want any bridge to be compatible with possible future dualling, or with possible future grade separation of the roundabout.

If the railway is raised it will still have to pass under Twmpath Lane. I imagine the resulting gradient would be more of a problem for the railway than it would be for the A5.

 

[DelW]

I was trying to find any details of this matter in the Northumberland Line thread. I don’t think it was ever clear exactly what the extra costs were for. I did wonder if the headline figure included all the rail work at Newsham including the station, the track redoubling southward, and the level crossing closure. Nonetheless it still seemed a relatively huge increase…

It's possible that some site investigation was done in the interim which found adverse geotechnical conditions, or even something like a buried industrial waste tip. Deep piled foundations, or removal and disposal of e.g. contaminated ground or hazardous waste, will add dramatically to the cost estimate.

If this is indeed to build a new rail bridge over the A5 Oswestry by-pass on the line to Gobowen then it will certainly not be a simple operation. Currently this is a level crossing so any rail bridge is going to require some long embankments on either side of the new bridge to allow sufficient road clearance height and this would require considerable land purchase either side of the road.

If it is there, the line crosses at an acute skew angle. A bridge for that alignment might end up like the Bletchley flyover rebuild, which is a very substantial structure.
However if the rail usage is limited to "a tram like shuttle service" as per the OP, it might be possible to build a viaduct more like those on the DLR, with sharp curves and (relatively) steep gradients allowing a more economical design.

 

[Llanigraham]

The A5 is a trunk road for which National Highways (formerly Highways England, formerly the Highways Agency) is responsible. Whilst I don't think there are any current plans to alter the A5, they might want any bridge to be compatible with possible future dualling, or with possible future grade separation of the roundabout.

If the railway is raised it will still have to pass under Twmpath Lane. I imagine the resulting gradient would be more of a problem for the railway than it would be for the A5.

Unlikely to want to grade seperate the roundabout to the north as it doesn't link to any major roads; just look at how they've "improved" the roundabout south where the A5 and 483 meet south of there which might have been better grade seperated.

Twmpath Lane to the A5 crossing appears to be 380 mtrs, so would that produce too steep a gradient? Minimum bridge height seems to be 6mtrs, so that would give a gradient of approx 1/63.