There have been several days where speed restrictions have had to be put in place recently - doubling the journey time from Wimbledon to Waterloo.
While this is bad enough, given that these trains depend on a flow of air from open windows for any form of ventilation (as there is still no a/c on most of the trains) this makes for an abysmal journey.
This is really a question for Network Rail, not SWR, but I can provide a bit of background info.
Some years ago I was involved with planning engineering access for a length of railway similar to Waterloo to Wimbledon. Without affecting train services, the maintainers got between 4 and 5 hours per night access on two out of the four lines. Allowing an hour to take any possession and current isolation and about 40 minutes to hand back the possession leaves just over 2 hours per night for actual repair work. Add to that that equipment will need to be moved from an access point to the location.
It often took four nights to undertake a job which would take maybe 6 hours if done in one session.
So there is a trade off: reduce the very early and very late night train services and give the engineers longer or stay as the industry is arranged now. To cut early and late services would need discussions with the DfT as they specify the level of train service and first and last workings.
Safety comes first, that is why temporary speed restrictions are imposed. It is also why it takes so long to block and isolate a given section of track.
So what is better, a longer journey time or the heightened risk of a derailment?
Well it is an issue for SW Railways as they're the ones I pay my money to and also the ones who get compensation from Network Rail that are not passed back to those affected.
SWR and all other operators pay Network Rail track access charges for the provision of serviceable railway infrastructure. That is why NR pay compensation to the train operators for delays caused by infrastructure problems. Passengers then claim against their train operators. Then of course there is TOC on TOC delays when money passes between train operators because of rolling stock failure or station problems.
If you want fewer temporary speed restrictions, take the issue up with the DfT who set the levels of train service which have almost excluded maintenance from large sections of the railway on weekdays. This then leads to more weekend possessions and disruption to get basic maintenace completed.
Delay attribution and settlement isn't that easy if truth be known, but I don't suppose SWR would be too happy if I explained much more from the little I know about it. It's complex, mind deadening and has the leaden hand of accountants resting on it. A pain in the "funamentals" for operators, and engineers alike!
Its just buck passing and a total lack of accountability reall then isnt it?
Yes, please refer to the Railways Act of 1993.
That set the ground rules for railway privatisation and a system of confrontation between train operators, the infrastructure managment and contractors. Add politicians meddling and allow to ferment for 25 years to get the current situation.
Why ANY major transport group tries to run a service and make money out of the franchising system I don't know.....