In the UK the longest "non-disruptive" possession that can generally be arranged is from about 01:00 after the end of the Saturday service to around 06:30 at the beginning of Sunday, but of course it does vary around the network depending on precise timetable. Mid week nights are typically much shorter- perhaps 01:00 to 04:00 but may be an hour or two longer- it largely depends where the rolling stock for the commuter service is stabled.
Sometimes it is possible to arrange to replace trains by buses from earlier in an evening, for example from 23:00.or in a few cases there are diversionary routes or 4-track railway when only 2 tracks are needed for the service late at night / early in the morning and the other two can be under possession longer.
Otherwise to get longer to undertake work, the travelling public must be inconvenienced further- perhaps by the use of buses or long railway detours all day on Sunday, so that engineers can be given a longer uninterrupted access- 54 hour and even 72 hour possessions can be arranged given the need and enough notice. Periods such as Christmas and Easter and other Bank Holiday weekends when most people take a long weekend are possibilities for this (but much hated by those who expect to travel by train then). This reflects that commuting to/from work is a major use of the UK railways; conversely in Eire the railway is most used over the holiday weekends, so for them such times are a bad time to undertake work.
The question really is whether it is better to divide the work into lots of small chunks that can each be done in a relatively short period, but needing very many of them- perhaps every weekend for a period of years- or is it best to concentrate all that effort into a closure of the line for an entire week (between Christmas and New year for some places; for the school summer holidays in other areas of the country- it depends on the local traffic pattern highs and lows).
So at one extreme "overnight closures" do not affect any timetabled passenger train services and therefore work can be undertaken disrupting few people, but it takes ages to do the job, is typically very expensive and needs lots and lots of separately designed packages all dependent upon the earlier one and so must be done in sequence- if one fails for any reason, much replanning and redesign.
At the other extreme "extended closure" means days or weeks without a proper (and sometimes any) train service- often called "a big bang". Of course there is some flexibility to "average" in this- if time is lost on one activity there is opportunity to gain some to compensate on another and so the overall programme might be met (whereas if each possession is a separate job then inevitably some will overrun and the railway re-open late sometimes; if the next weekend things go very well then all it means is the engineers get back home to bed sooner but can't "transfer time between shifts". Conversely if doing a big closure and a key person falls sick, the weather is very bad or some other unplanned event happens "all eggs in same basket" and the entire big job may suddenly go extremely wrong and a huge overrun of possession time might occur.
Hence you need to consider the various risks associated with the various approaches- what could go wrong, how likely it is, what the consequences would be. Think of it from the perspective of the designer / installer / tester / maintainer / signaller/ driver/ passenger etc. Think of the direct safety risks of getting confused about what should be undertaken where and when on a multi-staged project- particularly if trains continue to run in the area when the adjacent signalling is being altered. Think of the risks both the staff and the travelling public. Think about the commercial implications of the railway not being available to re-open on time in each scenario.
Sometimes it is possible to arrange to replace trains by buses from earlier in an evening, for example from 23:00.or in a few cases there are diversionary routes or 4-track railway when only 2 tracks are needed for the service late at night / early in the morning and the other two can be under possession longer.
Otherwise to get longer to undertake work, the travelling public must be inconvenienced further- perhaps by the use of buses or long railway detours all day on Sunday, so that engineers can be given a longer uninterrupted access- 54 hour and even 72 hour possessions can be arranged given the need and enough notice. Periods such as Christmas and Easter and other Bank Holiday weekends when most people take a long weekend are possibilities for this (but much hated by those who expect to travel by train then). This reflects that commuting to/from work is a major use of the UK railways; conversely in Eire the railway is most used over the holiday weekends, so for them such times are a bad time to undertake work.
The question really is whether it is better to divide the work into lots of small chunks that can each be done in a relatively short period, but needing very many of them- perhaps every weekend for a period of years- or is it best to concentrate all that effort into a closure of the line for an entire week (between Christmas and New year for some places; for the school summer holidays in other areas of the country- it depends on the local traffic pattern highs and lows).
So at one extreme "overnight closures" do not affect any timetabled passenger train services and therefore work can be undertaken disrupting few people, but it takes ages to do the job, is typically very expensive and needs lots and lots of separately designed packages all dependent upon the earlier one and so must be done in sequence- if one fails for any reason, much replanning and redesign.
At the other extreme "extended closure" means days or weeks without a proper (and sometimes any) train service- often called "a big bang". Of course there is some flexibility to "average" in this- if time is lost on one activity there is opportunity to gain some to compensate on another and so the overall programme might be met (whereas if each possession is a separate job then inevitably some will overrun and the railway re-open late sometimes; if the next weekend things go very well then all it means is the engineers get back home to bed sooner but can't "transfer time between shifts". Conversely if doing a big closure and a key person falls sick, the weather is very bad or some other unplanned event happens "all eggs in same basket" and the entire big job may suddenly go extremely wrong and a huge overrun of possession time might occur.
Hence you need to consider the various risks associated with the various approaches- what could go wrong, how likely it is, what the consequences would be. Think of it from the perspective of the designer / installer / tester / maintainer / signaller/ driver/ passenger etc. Think of the direct safety risks of getting confused about what should be undertaken where and when on a multi-staged project- particularly if trains continue to run in the area when the adjacent signalling is being altered. Think of the risks both the staff and the travelling public. Think about the commercial implications of the railway not being available to re-open on time in each scenario.
(02-06-2014, 02:36 PM)jenni.joseph9 Wrote: Hi,
I would like to know more about this topic.
Can anyone please help me out to get more information in the area of Extended closure/overnight and weekend closures.
Thanks
PJW