San Francisco used to have comparable headways when streetcars ran on
Market Street: look at historic photographs for the effect of a near
wall of streetcars along much of its length.
A not-so-secret secret is that better service is possible in the Muni
Metro when the signalling is inoperable and drivers are on "visual",
ie manually ensuring that they don't run into the vehicle ahead, just
like the way trains run on the surface lines...
Must have been nice. Yes on I.
The Key system had its problems and wouldn't -- contrary to the
belligerent and outright mendacious foaming-at-the-mouth in the pages
of the Chronicle by senior MTC staff and people like Quentin Koop or
Jim Hass -- be reconstructed in its previous configuration. What will
be needed _eventually_ is increased transbay capacity, and that either
means a new multi-billion dollar bridge or tube or making better used
of the existing bridge, via careful design of the new eastern span
today. The latter prudent, conservative step is what Proposition I is
about.
By the way, here are some Fun Facts about transbay passenger capacity.
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BART's Advanced Signalling System is supposed to get headways down
from 3.75 minutes to 2.25 minutes. (However, this is combined with
decreasing train lengths from 10 to 8 cars, so there will not be a lot
more capacity until BART buys a lot more rail cars.)
It is not feasible to operate peak-period BART trains much closer than
2 minutes because of delays incurred loading and unloading passengers,
primarily at the Embarcadero and Montgomery Street stations in San
Francisco. This is a basic limitation of the system which cannot be
fixed no matter how much is spent on signalling or other upgrades.
MTC's claims that BART will increase capacity by 50% are physically
impossible and outright fabrications.
Moreover, as headways approach 2 minutes system performance becomes
incredibly fragile: a single delay or malfunction anywhere causes
effects throughout the entire system from which it may be impossible
to recover in a period of less than hours. (Already BART regularly
experiences system-wide delays stretching into the p.m. rush hour
because of something like a single 6am failure of a switch in Daly
City.)
BART currently runs a total of 546 trains per weekday through the
Transbay Tube.
BART's present-day peak passenger/hour through the Transbay tube is
about 16,000. BART predicts 22,000/hour by 2010.
One ten-car BART train with carrying 1000 passengers (packed!, only
680 seated) every two minutes is a maximum of 30,000 passenger/hour
through the transbay tube in one direction. That is almost certainly
above the ultimate limit to BART capacity -- the practical limit
is likely to be considerably lower, because getting those 1000
passengers on and off the train takes time.
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The Key System/IER used to run trains as close as 64 seconds apart.
This was possible because the multiple platforms at the Transbay
Terminal allowed the next train to arrive while the previous train was
still unloading and loading. (BART cannot do this because it has one
one platform for each direction.)
In February 1939 there were 1,058 trains a day across the Bay Bridge
(600 Key System trains, 432 IER trains, and 26 long-distance
Sacramento Northern trains.) That is an _average_ of one train in
each direction every three minutes, all day. Trains ran as close as
63.5 seconds apart at peak periods.
The Transbay Transit Terminal was designed for peak passenger capacity
of 17,000 per 20 minutes (ie up to 50,000 per hour) though there were
never that many passengers. What this does show is that there is
capacity for huge numbers of rail and bus passengers, way beyond what
BART and automobiles can provide.
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The Bay Bridge has five traffic lanes in each direction. At peak
period, it carries about 9,600 vehicles per hour, or just under 2,000
vehicles per lane per hour. (This is heavily congested, and it about
the limit for road traffic.)
The most heavily-used bus lane of which I know -- the Lincoln Tunnel
linking New York and New Jersey -- can see over 700 buses per hour in
one lane, and carries 30,000 passengers per hour. (The Transbay
Terminal cannot accomodate this number of buses per hour; there isn't
enough space.) This shows that a dedicated transit lane can be very
effective, as Roy Nakadegawa always claims.
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