What is ATP, as used on modern trains?

ATP stands for "Automatic Train Protection" which refers to a type of train safety and control system. Some key things to know about ATP speed control:

• It is a signaling and control mechanism that monitors a train's speed and will automatically apply the brakes if the train exceeds speed restrictions.
• ATP uses coded trackside data, on-board sensors and train computers to continuously determine the permitted speed limit at any point.
• If the driver does not adequately slow the train at places like signals, speed restrictions, sharp curves etc, the ATP system activates the braking system to enforce safe speeds.
• Modern digital ATP speed control technologies include tools like EBICAB, TVM and ETCS used on high speed lines like the Eurostar to prevent accidents due to excessive speed.
• It is a train control system that can be equipped on locomotives, coaches, wagons, and multiple unit trains.

So in essence, the "ATP speed control systems" referred to on modern trains is technology that acts as an automatic failsafe if trains accelerate past designated speed limits, greatly improving railway safety and operation. It's a key safety feature of leading railway signaling platforms today.