I used to do this about 10 years ago for Connex South Eastern. There were three sections: Timetables, Rolling Stock, and Train Crew. Each section had Permanent Planners who did Long Term Plans (LTP), i.e. the normal timetable, and Temporary Planners who did Short Term Planning (STP) which were alterations for engineering work, mostly the weekends but also weeknights too.
I used to do STP timetables. You'd be given a week, which was numbered according to the number of the Weekly Operating Notice (WON) from Network Rail. The draft copy of this notice would detail all the engineering blocks (known as T3 possessions), with all the limits of the block (from such and such signal to such and such set of points on the Down Fast, for example), along with the times that the block applied. You'd then have to amend all the trains that would be on that line during those times by cancelling them, diverting them, terminating short, or starting forward of the block.
Our Train Planning Manager used to go for meetings with the Commercial section of the business and Network Rail, and would give you a rough plan of what was to happen in a 'Standard Hour'.
For example if Swanley to Rochester Bridge Junction was blocked on a Saturday, you'd divert the XX05 and XX35 departures from Victoria to Ramsgate, via Slade Green and Gravesend, stop at Strood for connecting buses, and then additional stops for all stations to Ramsgate. The detachment from Faversham to Dover would need to be re-timed.
The XX11 and XX41 would run from Victoria and terminate at Swanley. You'd then create a 'bus' in the timetable from Swanley to Strood calling at all stations except Meopham I think it was - where there wasn't enough room for a full sized bus to use the station forecourt, so a minibus would connect into the main bus at Sole Street. You'd need to make sure this minibus connected with the bus going in the other direction as well, so that only one minibus was used for the five minute journey!
Trains on the Sittingbourne to Sheerness line would need to be re-timed, again with consideration to trains on the main line coming in the other direction from the coast towards London.
That would just be one blockade!
I think the most number of alterations (cancellations, diversions, amendments, re-timings, additional trains, buses) I did was 1003, which was just for the Sunday of the weekend I was working on!
Junctions would need to be checked for conflicting moves whenever you re-timed a train. Also let's say Charing Cross was shut on a Sunday, and you're diverting trains to Cannon Street. There's six platforms at Charing Cross, and seven at Cannon Street - you'd be needing that extra platform as trains would be terminating there five minutes earlier, and leaving there five minutes later than they would at Charing Cross. You'd do a 'platform occupation' graph' to prove your plan would work!
All junctions would need to be checked when adding or re-timing trains to check for conflicting moves. Sometimes other trains would need to have 'pathing time' added as you tried to make the big shifting jig-saw that is the railway timetable fit together.*
Eurostar used to run into Waterloo back then and their trains were not 'standard hour' as it depended whether they stopped at Ashford or not. You'd liaise with Eurostar's planning department, as either of you sometimes needed one of the other's trains re-timing.
Fortunately South Central and Eurostar were the only other companies trains that we would come across, and as South Central was also Connex for a while after I joined, their planners were in the same office for a time.
Freight trains were sorted put by Network Rail, so we didn't need to worry about them.
At South Eastern it was such a large chunk of railway, that there were separate sections for Rolling Stock, who worked out what service arriving would make what service leaving, what depots and sidings would provide the trains needed for the service, and would have to do 'stock balancing'. So let's say there's a Bank Holiday Monday with Sunday service. Normally trains stabling on a Sunday night will be in the right place for a Monday morning, but this time you've got a Sunday service again starting up in the morning. Rolling stock would come to you asking for certain empty stock moves to be made additionally, others cancelled, or if a service could use a different platform so it could attach to another unit before it went to the depot. You'd need to be careful that there was enough time allowed for the driver to make the attachment, and if the train reversed anywhere there was a greater *driver's 'change ends' allowance for a longer train.
Similarly the end of Bank Hliday Monday's 'Sunday service' would need balancing for all the trains to be in the right place for Tuesday morning.
Also any attachments had to be thought about - are both parts compatible?
Train crew diagrammers would cancel diagrams and issue new ones, or amend existing ones. They had to take account of various allowances such as:
Preparing trains (different types and lengths have different allowances)
Walking time for various locations
Change end time (depending on class of traction and length of the train)
When breaks can be taken, also where - there are only certain locations where there are PNB facilities).
Ataching/Detaching
Maximum turn length
Route Knowledge (certain depots only sign certain routes)
Traction Knowledge (certain depots only sign certain traction - an extra complication when inworked there was that 375s were being introduced, but only a limited number of drivers at certain depots were trained on them).
DOO - some routes require a Guard, some drivers aren't DOO trained (Hastings drivers weren't).
As I've said there were the different departments at South Eastern because it was so large. Each section had about six weeks to do work for one weekend, and about 60 people worked there. Other roles included someone who published the informantion posters and did briefing booklets for station staff, and a Bus Co-ordinator who arranged with bus companies to provide all the replacement buses which had been timetabled.
However, at other companies Train Planners do all the work for a weekend - Traincrew (including buffet staff on some trains), Rolling Stock, and Timetables.
It was an interesting job, but could be very stressful as deadlines approached and blockades changed! I'm glad I did it though.
