It is half hourly during the peaks and on occasion trains run non stop.
Its not remotely comparable to a freight line festooned with ABCLs and similar being upgraded to a passenger line.
Most Bedford to Bletchley crossings are full barrier CCTV crossings, with the rest AHBs.
There is no prospect of more than one extra train an hour for the forseeable future, that being a Bedford to Oxford train that will stop at both Ridgmont and Woburn Sands (both adjacent to CCTV full barrier crossings) and likely Stewartby (for Wixams) as well (AHB).
If the line on to Cambridge is ever built and that results in vast number of trains and significant line speed increase they can do the crossings then, by when they will be in any case getting long in the tooth enough to need renewal if they are not replaced with bridges.
It is absurd to waste public money replacing modern level crossings for the sake of one extra train per hour, when the 125mph ECML remains littered with full barrier crossings and both lines to the West of England (100mph and 85 mph respectively) remain littered with AHBs.
Not to mention Eastfields Crossing in Mitcham with up to eight an hour each way over it.
Best to remove the planks before worrying about the splinters.
For the avoidance of doubt, I’m not defending Network Rail; I’m explaining the process which has to be gone through to comply with the law. Or trying to explain.
There is a difference between busy crossings that retain a broadly similar level of train service, and those where the train service is increasing.
Where a level crossing is expected to see an increase in rail traffic, or increase in linespeed, the effect on the risk to people who traverse the crossing (by any means)
must be reassessed. If the risk assessment for any one crossing shows an increase of anything other than a marginal amount, mitigation measures need to be investigated. This can range from the almost negligible, e.g. improving signage, or changing the layout of a footpath crossing, up to building a bridge. The costs of various mitigations need to valued against the safety benefit; there is a test of ‘reasonable practicality’ which very broadly suggests that if the cost of the mitigation is less than three times the Net Present Benefit of all potential benefits of closing a crossing (including safety benefit, maintenance / operational cost savings, future renewals costs avoided, and, crucially, time saving benefit to highway users); then that mitigation is reasonably practical and all reasonable steps should be taken to deliver it.
On Bedford - Bletchley there are 33 Level Crossings, of which 9 are MCB-CCTV. Whilst I am no expert on the line’s timetable, I strongly suspect that the number of trains that ran non-stop each day was in low single figures; the existing risk assessments are based on a total of 36 trains per day. Also, I don’t know how busy each train is - a crucial element to the risk assessment - but expect it to be small give the rolling stock. In very, very rough terms, if you double the train count you double the risk, if you quadruple the average loading on the trains, you quadruple the risk (for vehicular corossings) and a change in effective linespeed from most trains at slow speed to most trains at higher speed can make a significant difference depending on circumstances (in this case, I estimate somewhere between 2-5 times).
Now it is conceivable that even having done all this assessment, it results in no need to deliver any significant mitigation measures. That is quite probable for the MCB-CCTV crossings. It is more of a mixed bag for the 21 Footpath and User Worked crossing, and less likely for the 3 AHB Crossings.
Added to this is the effect on local traffic. If, as part of the consents process, the traffic assessment demonstrated a significant worsenment of congestion due to additional level crossing down time, the highway authority may have sought an amendment to the proposal to deliver a bridge. Whether this has happened or not I don’t know.
That's puzzling and annoying, given that, according to Wikipedia:
How many gas mains, high voltage cables, and busy highways did the Victorians have to divert / alter? What were the restrictions they had on noise, dust, etc. What engineering codes did they use? What were their competence and training arrangements?