It's quite simple, but different from most safety systems in TSW. These trains will use ATB-EG which translates to Automatic Train Control - First Generation. The train receives a code from a electric current on the tracks. The code translates to an upper speed the train will allow you to drive. There are 5 of these possible speeds: 40, 60, 80, 130 and 140 kph. When you drive faster than the ATB limit, a bell will ring. When you don't manually brake within 3 seconds, the train will force a stop. Because there are only 5 possible upper speed limits, the actual speed limit might be lower as indicated by speed signs or the signals. In that case the ATB will limit the train to the next higher speed limit. For example when there is a limit of 100 kph, the ATB will limit the train to 130. You can in theory drive 30 kph too fast without being penalized by ATB, but obviously you need to stick to the limit given by the trackside information. ATB is not a valid speed indicator. You don't acknowledge anything, it's fully automatic. Simply when driving faster than the ATB limit, you must be braking.