Page 108 - 捷運技術 第35期

100 Alstom Company New Enhancement of the Taipei Metro Signaling System

The new GM4000A switch machine will replace the previously supplied Model 5E switch
machines. The GM4000A uses 50% fewer parts than traditional switch machines and incorporates a
Brushless DC motor along with a solid-state amplifier. This improved design enhances reliability
and maintainability. Field obstruction testing and adjustments are also simplified with the help of
LEDs and a point-detector adjusting nut that is exposed and easy to adjust.

GM4000A Switch Machine

Redundant VPI units are being installed to maximize reliability and allow uninterrupted
operations during routine or un-scheduled maintenance. In a redundant VPI system, two identical
VPI units are installed within a signal equipment room. Normally, both VPI systems read all inputs
and process the logic simultaneously. However, only one of the VPI’s will have its outputs
energized. This allows only one VPI to control the interlocking while the other is always ready to
take over automatically if needed. Also, control of the interlocking can be transferred manually if
desired so that routine maintenance or testing can be performed on the other VPI. Maintainers and
controllers will certainly welcome this new feature.
One of the new features that will be most visible to the passengers will be the integration of
Platform Screen Doors（PSD）sub-system. The PSD sub-system will consist of a set of sliding
doors separating the platform from the train track at the stations. The doors will remain closed
except when there is a train parked at the platform. When a train arrives at the platform, and is
safely stopped, the PSD will open to load and unload passengers. The PSD will then close before
the train departs. The separation of the tracks from the platform with PSD will be an obvious
improvement to the safety and comfort of the passengers.
The new and improved systems described above are already in the design, build and
installation stages. We will be able to see them in operation in the very near future. However, in
order to maintain a world-class metro system, one cannot rest on their laurels. The creative
engineers at Alstom Signaling are already hard at work designing the signaling systems of the future.
Some of the innovations that are being designed include improved electronic diagnostic systems,
enhanced passenger information systems, and more robust wayside hardware. Alstom Signaling will
always be hard at work to make sure our passengers arrive safely at their destination in the most
efficient and reliable way.