Re: [MELB] Speed of metropolitan trains

["Derick Wuen" <cullend@webone.com.au>]

Roderick Smith wrote in message <01c0b830$b0b58140$b68a17d2@rodsmith>...
>I have calculated a base case on a typical station spacing being 1500 m,
>with trains allowed 65 km/h, and 20 sec stopping time.  Using the
>specifications for Melbourne's double-deck set: 0.75 m/sec/sec
>acceleration; 0.9 m/sec/sec service braking:
>
>accelerate for 24 sec (216 m)
>cruise for 61 sec (1104 m)
>brake for 20 sec (180 m)
>stop for 20 sec
>The cycle takes 125 sec, giving an effective average of 43 km/h.
>


I have turned up the following speeds and acceleration rates for diverse
emu/dmu commuter stock. It would be interesting to fill in the gaps, and add
the Perth emus to the list.

Operator   Stock       Acceleration Service Braking Max. speed
                                    m/sec^2            m/sec^2
kph
QR             EMU             ?                          ?
100
Cityrail Comeng DD    0.76                    0.76                  113
Cityrail Goninan DD      ?                          ?
115
Met      Comeng           0.80                    1.00                   115
STA     SA DMU            ?                           ?
120
Cityrail Tangara           0.80                     0.90
130
Cityrail Vset DD          0.65                     1.40                  130

The Melbourne Comeng stock sit ok in this comparison. Recent mods by Connex
probably change the acceleration and deceleration rates for the worse. Even
so it would seem that rolling stock performance is not constricting overall
train performance in Melbourne.

Neither should station stop times be radically different from Cityrail...
the number and width of doors is probably much the same.

Look to track and signalling for engineering improvements. For e.g. the
"express" centre track Burnley to Camberwell was signalled for 45 mph (70
kph) running when built. Has it been improved?

What about a conspiracy theory? The privatised trains operate under service
level agreements which punish operators for late running by fines. Does this
provide an in-built bias to conservative timetabling?

Like many airs and variations on management by objectives, SLAs often result
in restrictive practices and anti-innovative behaviour. I see the same thing
with workplace performance agreements every day. Minima become maxima, and
users suffer.

The gap between actual performance versus theoretical achievability in your
Melbourne to Belgrave example is huge. The privatised train SLAs should have
a service IMPROVEMENT objective!

Finally, I don't think the Paris Metro is a good example for any Australian
city, none of which have the density of population in/near the CBD nor the
road congestion that Paris has inside the city walls. Also it is doubtful
that any government in Australia could sustain French financing (tax and
debt) policies to create and operate such a thing. A better comparison would
be with RER, which to performs a similar role in longer distance commuting
as Australian systems. Without looking at any precise figures, the RER seems
to perform much the same as Cityrail, both on an engineering and financial
level.