32 鐵路列車自動控制系統中之列車自動監督系統為：
(A) ATP
(B) ATS
(C) ATO
(D) ATB

資料來源：https://www.railwaysignallingconcepts.in/railway-signalling-automatic-train-control-protection-atp-ato-ats/

(A) ATP列車自動保護系統(Automatic Train Protection）

車載裝置接收地面限速資訊，經資訊處理後與實際速度比較，當列車實際速度超過限速後，由制軔裝置控制列車制軔系統制軔。以達到列車在停車點前停車或在限速點前實際速度小於限速值的目的 

Automatic train protection (ATP) is a type of train protection system which continually checks that the speed of a train is compatible with the permitted speed allowed by signalling, including automatic stop at certain signal aspects. If it is not, ATP activates an emergency brake to stop the train.^[1] 
(B) ATS自動列車停止裝置(Automatic Train Stop)

自動列車停止裝置的原理，是當列車經過訊號發射器時，超過訊號所容許的速度，甚至冒進停止訊號的情形，此時ATS會啟動列車上的緊急制軔，將列車停下來，避免發生事故。

Automatic train stop or ATS is a system on a train that automatically stops a train if certain situations occur (unresponsive train operator, earthquake, disconnected rail, train running over a stop signal, etc.) to prevent accidents. In some scenarios it functions as a type of dead man's switch. Automatic train stop differs from the concept of Automatic Train Control in that ATS usually does not feature an onboard speed control mechanism.  
(C) ATO列車自動運轉裝置(Automatic Train Operation）

ATO裝置主要讓列車收到指令後便自動開車，沿途根據訊號系統的指示來行車，到達停車站時自動停車。ATO裝置可以根據自動列車控制裝置（ATC）或自動列車保障裝置（ATP）等訊號系統所提供的訊號自動加減速，使用ATO裝置可以令列車減少加減速的時間和長度，以增加列車的班次。

根據國際公共運輸聯合會 (UITP)的定義，自動運行等級（Grades of Automation，GoA）分成五等： 
(D) ATB

• 自動列車停止裝置（ATS）
• 列車自動運轉裝置（ATO）
• 自動列車控制裝置（ATC）
• 列車自動保護系統（ATP）
  
• 自動列車警報裝置（AWS）
• 調度集中系統（CTC）
• 通訊式列車集中控制裝置（CBTC）

Automatic train control (ATC) is a general class of train protection systems for railways that involves a speed control mechanism in response to external inputs. For example, a system could effect an emergency brake application if the driver does not react to a signal at danger. ATC systems tend to integrate various cab signalling technologies and they use more granular deceleration patterns in lieu of the rigid stops encountered with the older automatic train stop technology. ATC can also be used with automatic train operation (ATO) and is usually considered to be the safety-critical part of the system.

Over time, there have been many different safety systems labeled as "automatic train control". The first was used from 1906 by the Great Western Railway, although it would now be referred to as an AWS (automatic warning system). The term is especially common in Japan, where ATC is used on all Shinkansen (bullet train) lines, and on some conventional rail lines, as a replacement for ATS.