As a former trained signaller in Switzerland, I have to say that a lot has changed over time, even in the event of disruption. In the past, with the local manning of the stations, you had a lot to do if you were directly affected or you just had to show customers the way to the replacement buses.
Today, most of the standard-gauge network is controlled remotely by the four traffic control centres. There, the railway operation is divided into so-called "sectors", which are divided according to the traffic flows. These sectors are managed by a team. This team consists of 3-5 signallers, a sector manager and a customer information specialist. If possible, a disruption is dealt with within such a sector. This includes operational tasks, organising replacement services, coordination with the TOCs and customer information. If necessary, help from other sectors or from the back office can also be called in. However, this also increases the coordination effort within the team, so there are limits to this approach. In the event of major incidents, the head of the control room or even a crisis team may also be called in. As all of these traffic control centres are networked with each other, there is no longer any need for numerous consultations between the individual stations that were previously conducted by telephone.
Prepared checklists with alternative concepts are generally available for bus services in the event of interruptions. These lists contain contact details for the bus companies as well as journey times and routes. This is done in consultation with the bus operators. The bus stop locations in the event of a disruption are also signposted at the railway stations.
The exact functioning of such an operations centre is of course constantly being adapted.
The high degree of automation has led to major changes in the work of a signaller over the last 20 years. Many tasks are automated, the daily timetable is usually "programmed" and only deviations and disruptions have to be processed or reprogrammed manually.