HowardGWR - I think I am right in saying the submission wasn't made by Network Rail until June 2015. It all seems to have been done on a 'just in time' basis. Leaving it so late, with no proper engagement beforehand was a deliberate ploy?
infobleep - I believe that if Network Rail had submitted an honest assessment the outcome would have been different. The planning authority got tough when Network Rail flooded the site with workers and carried on working until the court order was served.
It's not nearly as simple as that - Network Rail have extensive legal powers to build, maintain and operate the railway, they have the legal right to remove level crossings, barriers, signal boxes, stations and to erect fences, masts, signals, electrification, to rebuild bridges and do many other things without having to seek planning permission.
The process is known as permitted development - Network Rail tell the local authority what they will be doing and under what legislation it will be carried out, the local authority can only intervene if they feel Network Rail is in error and that they're doing something that isn't covered by the railway related legislation.
In this case, Network Rail have the legal powers necessary to remove the level crossing gates and to install new gates without having to do anything other than informing the local authority they will be doing something under their permitted development powers. Where it becomes much more complicated is where Network Rail's powers conflict with that of the local authority, in the area around listed buildings. The powers NR has and which the original railway company had didn't anticipate railway buildings being listed.
To be quite clear, Network Rail do not need permission to replace the gates, they need permission to change the environment around the signal box, if they can install a set of gates which doesn't change the environment, or the local authority finally accept that a modern set of barriers does not look out of place, they'll get the permission they need to make the necessary changes. They can of course appeal and make the case that it doesn't matter that the environment around the signal box has changed, this has happened throughout the history of the railway, just look at the trains which go past it, if LBC were being especially pedantic, they would insist on steam trains going past the box to maintain the environment.
Network Rail could, if they were really being quite legalistic about this, have obtained their own injunction which would have prevented Lewes Borough Council from seeking an injunction, though this is quite a complicated legal process.
What will happen now, unfortunately for Lewes residents, is that your local MP will be informed by the Transport Secretary to explain the case for the level crossing being replaced, and that the local authority will be told in no uncertain terms they'll be looked at unfavourably in future budgeting cuts and funding rounds if they don't stop being awkward.
Or Network Rail will win on appeal - there's hundreds of boxes up and down the country which are listed, and which have been demolished, moved or have had their crossings and environment changed. LBC isn't going to avoid what's coming, it's putting off the inevitable.