<[snipped]>
>During peak service there is _always_ a huge queue of vehicles
>entering outbound Embarcadero from MMT or MMX; often four or five
>trains are visible to passengers on the platform. These vehicles load
>slowly and inefficiently because they must all queue to await the one
>single loading location at the west end of the platform. If some
>trains could load from the inbound platform -- subject of course to an
>outbound path being available ahead of some of the trains boarding
>opposite, and subject of course to not causing excessive delay to
>inbound service during the crossover operation -- then it would
>actually speed up metro operation and throughput to operate using
>Embarcadero diamond _in conjuction with_ MMT. Remember that in
>close-headway urban rail operation it is dwell time, determined by
>vehicle and platform throughput, which almost alone determines
>headways. Signalling and speed are secondary issues; which is why
>ATCS was such a criminal waste of resources. Overlapped boarding of
>multiple trains increases passenger throughput, which increases system
>efficiency. Turning back some trains from Embarcadero inbound via the
>crossover would achieve that. (It would also slightly increase the
>system-wide level of service by decreasing the non-revenue time wasted
>in MMT.)
Outbound operation, historically, has always been faster than inbound
operation. Once the train leaves Embarcadero, it runs quickly, loads
quickly, and is out of the way, and its place is quickly filled by the next
train, etc. The queue of trains behind it are empty (with the exception of
the ones coming from MMX), and it doesn't matter as much to have them wait.
Having a train use the inbound platform to go outbound will always hold up
the trains behind it, and it will confuse an already frustrated throng of
people waiting at Embarcadero. Isn't a queue of empty trains waiting to
load better than a queue of inbound trains, all with passengers aboard,
stuck between stations? I would think so.
>During off-peak service there is usually a free path available for
>inbound trains either directly into the outbound platform or for them
>to depart from the outbound platform and cross over. And if there
>isn't, operation can fall back to MMT. MMT was intended to address
>path contention over the diamon at times of very close headways.
>Off-peak, headways are not close, and so _always_ using MMT results in
>a 4+ minute non-revenue-service penalty to _every_ trip on the system,
>which results in a degraded level of service system wide.
On Friday, there were several instances when the CCO, after a gap in
service, routed an inbound train to the outbound platform with the diamond.
This is one instance where it works.
Why are you so worried about this "4+ minute non-revenue-service penalty"?
In Boston, every train arriving a terminal discharges its passengers, goes
into a non-revenue layover point, and the personnel prepare for the next
revenue trip by changing ends.
>Basically, you should only use a slower and less efficient way of
>running trains if operational constraints preclude the alternative.
>Which means that trains should only be sent into MMT if there is no
>way to turn them back using the Embarcadero crossing.
>
>Not only are these "theoretical" scheduling arguments, they are widely
>implemented on any number of rail systems. Stub terminals with tail
>tracks aren't uncommon, and neither are service patterns far more
>demanding than those in Muni's little trolley system.
"Muni's little trolley system"? How dare you belittle our [third]
world-class subway, Richard. <g>
>
> In a future signup, the M-Oceanview is going to Proof-of-Payment,
> with 2-car trains and one operator. Now, changing cabs at Caltrain
> is easy. All the doors open, the train is in Cab/Street operation,
> and the motorman has anywhere from 5 to 17 minutes to depart.
> Changing cabs in a 2-car train in the MMT will not be that easy,
> and, in fact, may be impossible. Trains will be in auto mode
> entering MMT, which precludes opening a side door even when
> changing cabs. Once the motorman opens the door in a location
> other than at the designated platform stop, ATCS is lost. The only
> solution to this dilemma is for Muni to provide a fallback
> arrangement back to Embarcadero to handle this line. Back to
> Square One!
>
>I'd fix the software so that opening a door and walking along the MMT
>side platforms is possible. Or I'd never have written software which
>had such a bug. (Or I'd have software drive the trains into and out of
>the turnback and have the operators meet them back at the platform!)
The M-Line "two-cars-with-one-operator" aspect of POP, which was supposed
to start with the April 3 signup, is on hold. The union rightly pointed
out that there are not enough cars available. During the week of February
15, nearly half the fleet was out of service, many cars with ATCS defects.
I have no idea if POP will begin April 3 as scheduled, but with present
schedules. In any case, having the operator change cars in the MMT (using
the side doors on each car to go between cars) is clumsy and
time-consuming. The idea of MMT is ostensibly to speed getting cars in and
out of the pocket tracks. It works with one car but not with two.
To have no operator on the train in the MMT is theoretically OK, but what
happens if the train going into the MMT is in cutout?
Muni has not thought this through at all. ARRGH!
Peter Ehrlich
F-Line Operator
Green Light Rail Division
<norcalrr@sprynet.com>