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Raja Azizi Raja Daud B.E (Hons) in Electronic

Union Switch & Signal

The Automatic Train Protection (ATP) System deployed by KTMB into their double track network covers from Rawang to Seremban inclusive of the branch lines to Port Klang and Sentul in 1996 and now expanding to cover the main line between Rawang to Ipoh. The system supplied is the L10000 ATC II, an intermittent ATP system, manufactured by AT Signal System AB Sweden. The System consists of two key components known as the ATP Wayside and ATP Onboard Systems.

The ATP Wayside System functions to provide the track information to the Onboard System. The information is transmitted in form of serial data, called telegrams. These telegrams may contain the following; the maximum permitted line speed, announcement of a speed restriction and distance to the restricted location, the aspect of the currently passed optical signal, the aspect and distance of the targeted optical signal, information to cancel signal control speed, train category and other sundry information. The required information is transmitted to the ATP Onboard System through equipment called transponders installed on the track.

ATP Onboard system contains the central processing unit (CPU) and several interfaces receive wayside information from the transponder through an antenna, which is installed underneath the train structure. The CPU evaluates the wayside information, as well as the data keyed on driver's data panel such as train maximum speed, deceleration factor, brake delay time and train length. The results from the evaluation are displayed on the driver's panel i.e. maximum permitted speed, target speed and distance to target (if target speed lower than maximum permitted speed) as driver's guidance.

The ATP onboard system will then perform the supervision depending on the evaluated information and intervene by initiating a brake application, either service or emergency brake, if the driver fails to react according to the presented data.

This paper is focusing on the new product developed to reflect the technology evolution and also part of the engineering development to improve equipment features besides ensuring continual support to existing customer in replacing obsolete equipment without necessitating major modification. The equipment called an Encoder, forms part of ATP Wayside component used to encode signalling or other control information into ATP telegram that can be transmitted to the ATP Onboard System through a transponder. There are two different styles of encoders both producing the same end result. Their difference in operation and installation will be explained in this paper. They are called the ATSS Encoder Type II and the US&S Microlok II ASES Board.