On 2008-11-07 23:46:29 +0000, D7666 said:

On Nov 7, 2:26 pm, Robert wrote:


At the risk of being pedantic the S-Bahn in Munich schedules 30 trains
per hour


I have commuted for short periods on the Munchen U-bahn and S-bahn and
was very familiar with it, although I've not been there in a while to
seriously use it apart from the airport links.

Nowhere on the Mch S-bahn stammstrecke (the core section) are there
junctions of any sort on the twin track core - only at the ends. The
equivallent scenario for Thameslink is no junctions at all anywhere
between West Hampstead and Blackfriars *and* to make the analogy
correct both of those locations would have to have 4 each dedicated TL
platforms.

It's a bit more complicated than that. I think that you will find that
the Stammstrecke is defined as the section from Pasing to
Munich-Ostbahnhof, a distance of marginally over 7 miles; it is not
just the central tunnel section. (By my calculation I make West
Hampstead to Blackfriars a bit over 5 1/2 miles). Working from the
west, 4 routes come together at Pasing, which has 4 S-Bahn platforms
paired by direction; it is then a two track route right through to
Munich-Ostbahnhof with grade separated junctions at:

(i) Laim where the S1 and S2 lines join and leave which has 1 eastbound
island platform with 2 faces and 1 westbound platform. The eastbound
junction points are just to the east of the island and the westbound
junction points are just to the west of the platform.

(ii) Donnersbergerbrücke which has 2 island platforms - 1 eastbound and
1 westbound allowing cross platform interchange for passengers between
the Bayerische Oberland Bahn (BOB) trains and the S-Bahn. The S7 coming
from the south, which shares tracks with the BOB trains, also joins and
leaves the Stammstrecke here. There is another very steep grade
separated junction just to the east of Donnerbergerbrücke which allows
the BOB trains (which are DMUs) to run into the Hbf, i.e.
Donnersbergerbrücke has grade separated junctions at both ends of the
platforms permitting the platforms to be paired by direction. (The BOB
serves towns south of Munich in the foothills of the Alps).

The next station to the east is Hackerbrücke which is simple island
platform. The central tunnel starts just to the east and runs to just
west of the Ostbahnhof which has 2 islands for the S-Bahn. The inner
faces are used for the S5 and S6 which reverse there (and head to the
south on a bridge over the tracks into and out of the tunnel) and the
outer platforms for the 3 routes continuing to the east and north. The
S7 terminates here.

You are, of course, correct in saying that the stations at each end of
the Stammstrecke have 4 dedicated S-Bahn platforms to cope with the
traffic density, but there are junctions in between. It works because
it has been properly designed.


On top of that, Mch S-bahn is equipped with LZB. AFAIK this is unique
among German S-bahn lines ... Mch Pasing to Mch Ost was equipped for
LZB operation from 12/2004 ... IIRC it was set up for 28 TPH although
might have been tweaked since.

For those who do not know, LZB ''Linienzugbeeinflussung'' generically
is a transmission based train control signal system. It exists in
several forms on both very high speed lines and dense close headway
metro lines ... no lineside signals, cab signals only, and operates
by setting target points based on location of preceding train or state
of the ''guideway''.

I am loathe to post a wikipedia link but this is about the only
overview I know of (in German but you can wiki translate it)
http://de.wikipedia.org/wiki/Linienzugbeeinflussung

Absolutely, the LZB is /very/ impressive. I'm sure the Munich system
couldn't work as it does without it. Trains close up to about 20 or 30
metres separation; if a train is stationary in the platform you can see
the front of the next one just inside the tunnel. When a train restarts
the next train can be entering a platform before the rear of the
previous one has cleared it. It's even better if you stand behind the
driver and look over his/her shoulder... The first time I did it I
flinched - the train in front is so close it /can't/ be right!



AFAIW such grandiose signalling systems do not form part of Thameslink
Program ... it will retain conventional trackside aspects with TPWS
and AWS. ISTR Roger Ford referred to this in MR a couple of years back
(although things might have moved since then).

A pity, when you consider that Munich, a city of 1.3m inhabitants, with
probably as many again living within 20 miles or so, gets a grown-up
railway while London, the powerhouse of the country with over 10m, gets
a cobbled together Hornby set.



If I thought Thameslink was getting LZB then I'd not have made the
remarks I did.

BTW ... the Jubilee (and Northern, Piccadilly) line signals upgrade is
to LZB ... Seltrac S40 is an LZB ... it even says LZB on the processor
cabinets/

Then there is hope for us yet!


--
Robert