[Rescue Muni] Re: Response to Max Pong re: ATCS

Richard Mlynarik (Mly@POBox.COM)
Mon, 31 Aug 1998 10:39:13 PDT

From: Peter Ehrlich <norcalrr@sprynet.com>
Date: Wed, 26 Aug 1998 22:12:09 PDT

On August 26, 1998 at 1243pm, you write:

<[snipped]>
>
>Re: ATCS. The three big _design_ (rather than implementation) shockers
>for me are:
>
>(a) The Embarcadero scissors crossover is never used and never to be
>used for turning back trains. [...]

On the contrary, Richard. On Saturday, when an LRV broke a pantograph in
the MMT and it was necessary to shut off the power for a time, the old
"Embarcadero diamond" was used. So it can still be used as a backup
measure.

My point was that it isn't being used a matter of course. When there
is a path available -- which the train control system of course knows
all about -- it should be the most favoured route. The aim should be
to maximize revenue service.

>A competent and "advanced" train control system would dispatch trains
>bidirectionally from either Embarcadero platform according to path
>availability (ie whether there are potentially conflicting arrivals
>from either direction) in order to maximize service levels.

Possible, but impractical. In addition, it would confuse the
passengers even worse than they are stymied now.

But they've dealt with it for decades! They're trained... if not docile.
The only thing needed is a reliable platform indication of which is
the next departing train is and what its destination is.

Not only that, but even BART passengers can deal with it: quite a
number of rush trains cross over and terminate at Montgomery, and
BART's relative peak frequency ("relative" meaning the ratio of the
time the longer crossing train fouls both running tracks to the longer
scheduled headway) is roughly comparable to Muni's.

The level of "impracticality" depends solely on the density of
conflicting traffic. My point is that often there aren't conflicts,
and at those times the most expeditious and efficient route should be
selected, meaning in and across (or across and out) the Embarcadero
scissors/diamond/whatchamicallit.

I was surprised and disappointed to find this isn't the case.

More trains carrying more passengers, fewer sneaking about in MMT!

[... rest of message elided...]

PS A worldly Muni observer would never need to use the words
"surprise" and "disappointment" together in the same sentence.