Yes this is true. According to CSC, the Swiss did this:
A superprecise dispatching system designed and implemented by the Swiss Federal Railway (SBB) with CSC is helping them run like clockwork. The Rail Control System (RCS) was developed over four and a half years by a team of about 100 rail and technology experts. CSC’s Matthias Krista, Benedikt Soom, Frédéric Auberson and Gilles Iachelini played key roles in the architecture, business analytics and software implementation.
RCS is a powerful solution for analyzing complex interactions between trains and providing fast, accurate operational data to dispatchers, ultimately keeping trains on time and passengers happy.
The results of RCS can be seen here:
RCS provides near-real-time information on the current operational status of approximately 2,000 trains and 3,000 kilometers of track, and their corresponding switches and signals in the Swiss Federal Railways system. Overall punctuality has improved from 94 percent to 96 percent, making Switzerland the leader in international punctuality statistics.
So, as you can see, they are the most accurate and precise train system in the world. Apparently, Swiss people are generally very punctual, and it has been said that they only lose one minute of time per year. I generally lose one minute an hour, being late to most things, including going to bed.
Enough of that, Swiss trains are accurate, and that's for sure.
To help you visualize this, try looking at this:
That is the train tracker of SBB. It is a realtime tracker of the trains around Zurich.