On Sun, 20 Jan 2008, Mr Thant wrote:

On 20 Jan, 16:31, Tom Anderson wrote:
Do you mean that the new communication system will be carrying messages
from the old control computer to the new trains? Kind of like attaching a
scan of a postcard to an email? Will the new on-train computers thus be
running an emulation of the old system's logic, or will there be a
translation step on the track side that changes "420 ppm" to "you have any
infinite clear distance ahead of you"?

I appreciate that you may not be privy to such fine details!

The only thing I’’'m privy to is this here Metronet newsletter:
http://www.metronetrail.com/webfiles...Issue_8_sm.pdf

"The new system will then run in tandem with the old until the old
trains are finally phased out. To achieve this, the new equipment
rooms will take information from the old and convert it into a safety-
critical radio message to be transmitted to the new trains."

"The new trains will initially work with new automatic train control
equipment in conjunction with the existing signalling system whilst
the existing trains will continue to operate with the existing
automatic control system. "

It sounds more like your latter scenario.

It certainly does. Cheers for the quote.

tom

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Taking care of business