London Banter - Why isn't the 2009 stock walk through like the S stock?

wrote in message

On Thu, 12 Jan 2012 16:09:46 +0000 (UTC), d
wrote:

Some ideas should stay in the box because they're just a little bit
daft.

Agreed -- for a line that's entired in small tunnels, OHLE really
would be a waste of space.

Not to mention potentially dangerous. There would probably be mere
inches from the train roof to the wire so it might not take much for
it to touch the train and electrocute everyone.
Wasn't part of the concept that the trains would have a much lower
floor and platforms , very similar to a low floor bus or tram. may not
have been room under for live rail clearance.
http://www.flickr.com/photos/stephen...n/photostream/
Shows a bogie mock up.
Doubt if a wire would be used ,more likely a rigid bar type conducter
like in Barcelona and other places including the odd bit in the UK
like at movable Bridges.

I found this write-up in Railway Gazette from Aug 1998:

"Since 1995, under the leadership of the then Rolling Stock Chief
Engineer John Vint, LU engineers have been working up a concept design -
currently known as 'Space Train' - that aims to carry 40% to 45% more
passengers in a Tube train.
Combined with moving block signalling to reach 90sec headways (40
trains/h), the theoretical ability to double Tube capacity has been
demonstrated - though much costly civil engineering would be needed at
congested stations like Victoria to achieve this throughput in practice.

LU Rolling Stock Engineer Malcolm Dobell is currently in overall charge
of the Space Train project. Development of the concept design is being
led by Senior Design Engineer Chris Sharp. Dobell explains that the
initial focus is on the Victoria line because the 1967 stock is coming
up for renewal. Tunnels and stations were built in the 1960s to higher
and more consistent standards, the whole route is in tunnel, and there
is no interworking with other routes such as occurs on the Piccadilly,
Bakerloo, and Jubilee lines to add complications.

At 3078mm, Space Train is 436mm wider at waist height than existing
stock, which already overhangs the platform. The floor is 18 mm lower
than the 1967 stock at the car centreline and 139 mm at the doorway sill
plate in the tare condition, giving level access from LU's 520mm high
Tube platforms. Before it can operate, therefore, platform edges must be
set back by about 170mm.

In addition, the intention is to abandon the third and fourth rails on
the track in favour of a roof-mounted collector running on a positive
rail, with negative return through the running rails in the conventional
manner for metros. Installation of platform screens with doors matching
those in the train may permit an increase in voltage, say to 1·5 kV. To
put the rail beyond the reach of umbrellas poked into the gap above the
vehicle doors, the conductor rail would be raised in the stations by 890
mm compared to the running tunnels.

Although the engineering aspects of transitional operation with a mixed
fleet have been carefully weighed, the picture that emerges is of a
quite fundamental line-by-line conversion programme extending over some
30 years.

A question currently being addressed by LU is how Space Train
development fits into the private-public partnership framework announced
by Deputy Prime Minister John Prescott on March 20. Dobell says LU's
immediate objective is to establish, through studies and contracts with
suppliers, that the proposed capacity increase is technically and
operationally feasible.

This would not necessarily require a prototype train. Instead,
development contracts would be placed for specific components such as
overhead current collection in a Tube tunnel, the articulation and bogie
design with 430mm wheels, wide gangways between the cars, and the
propulsion equipment.

At the same time, precise measurement of tunnels and structures would be
carried out, and the aerodynamic effects of reducing the annular space
around the train assessed.

This would pave the way for concession agreements with the proposed one,
two or three asset management companies that included a requirement to
increase capacity under defined circumstances. The intellectual property
rights to LU's concept design would then be made available to
concessionaires and rolling stock suppliers, but it would be up to them
to work out the details.

Clearly, there would have to be provisions in place to prevent mutually
incompatible systems being developed, while still allowing the maximum
freedom to innovate - a conflict which has yet to be resolved.

The Space Train concept

SPACE TRAIN, as currently conceived for the Victoria line, would
probably consist of 12 articulated cars on 13 bogies totalling 137·6m in
length, compared to 129·8m for a pair of four-car units of 1967 stock.
With fully-automatic operation and platform screens, it is only
necessary for the 24 double-doors, each opening to a clear width of
1664mm, to be inside the 132·6m distance between relay rooms at each end
of the platforms.

Fig 1 shows the layout proposed for a 12-car train, although 10 to 13
cars are possible within the overall length fixed by platforms. A key
parameter is the gap between platform and door sill; this must be
limited to 100 mm for level access by wheelchairs and prams, whereas
250mm exists now at Bank station where LU's most sharply curved
platforms are to be found. Fortunately, Victoria line platforms are
virtually straight. Even so, a hinged beam pivotted at each end onto
adjacent cars at the articulation fills the small gap that exists at
convex platforms. Gaps down to 40 mm are the aim.

Floor area is what counts when it comes to standing passengers. LU
assumes 6/m2 at crush load in the aisles between longitudinal seats, and
8/m2 in vestibule areas around the doors. On this basis, there is a 53%
increase from 178 to 274m2 per train compared with 1967 stock. The
increase in standing passengers is even greater at 63% under crush load
conditions because the effective vestibule area is so much larger. The
wider aisle between longitudinal seats (1512 against 981mm) should make
for more effective use of this standing area than on existing trainsets.

While much of the increase in floor area stems from the extra car width,
with seated passengers set back to exploit the near-circular
cross-section of Space Train, there are only 220 seats compared to the
304 in 1967 stock. Chris Sharp points out that if 90sec headways were
introduced, the total number of seats per hour would actually rise by
8·5% from 8 106 at today's 135 sec headways to 8 800.

Standing area includes the 1900mm diameter turntable at the
articulation, which has to accommodate only a fraction of the rotational
displacements common in light rail vehicles.

Nominal crush load is expected to rise from 1564 to 2273 passengers per
train, a 45% increase. However, it is expected that the continuous 1·5m
wide walkway throughout the train, compared with today's narrow
inter-car doors (which passengers are only supposed to use in emergency)
will lead to better distribution of passengers along the train.

Sharp believes the extra height provided by a lower floor will allow
tall people to stand closer to the sides and curved doors, and therefore
boost loadings. As Fig 2 shows, the 95th percentile man who is 1876mm
high could stand fully upright with his shoulders against a side wall or
curved door in Space Train, whereas in 1967 stock he can only do so in
the centre aisle.

That said, your reporter who is 1900mm high routinely stands jammed
against the doors of 1967 stock, if not exactly in comfort.

The lower floor is central to the Space Train concept. The idea actually
originated in 1995 with the roof-mounted conductor rail, which in turn
stemmed from a desire to get rid of the present system which seriously
inhibits good quality track maintenance. Since then, it has been driven
forward by the need to achieve level access for mobility-impaired
passengers on the Underground in years to come, and by the benefits of
greater headroom.

Flattening the roof slightly means that Space Train is 35mm lower than
1967 stock at 2838mm. A design has been produced for LU by Brecknell
Willis which mounts a shallow inverted light alloy rail with a stainless
steel cap within the nominal 200mm available between train roof and
tunnel segments.

Except for Northumberland Park depot, the Victoria line is all in bored
tunnel. For the 42% of Tube lines which are in the open air, on tracks
occasionally shared with full-sized trains, catenary and a pantograph
with appropriate reach will be necessary.

Bogie debate

The three-axle bogies proposed by Sharp have already proved to be a
controversial feature with manufacturers. Dobell comments that 'we need
to bottom-out that debate and are still open-minded; we have seen
proposals for bogies with 1, 2, 3 and even 4 axles!' In fact, Sharp's
'bogie' (Fig 3) has two frames linked to the bodies on each side so that
all three axles are steered through curves. The end bogies have two
axles with only the outer wheelset steered. Clearly, two-axle bogies
throughout would be preferable, but Sharp argues that they would be
'right on the limit' for wheel/rail contact stresses.

Diameter of the wheels when new is 430mm, compared to 360mm in four-axle
bogies under rolling motorway wagons that carry complete lorries in
central Europe. Sharp says he would welcome information or reports on
the performance of small wheels (less than 650mm) from operators with
experience extending over several years.

Dobell notes that 'most of the debate with manufacturers that we have
had so far has been generated by these bogies (above), the small wheels,
and to a lesser extent the reduced underfloor space for equipment.'

AC motors slung under the car body would drive the outer axles of each
articulation bogie; the centre axle is unpowered because of the tight
space under the articulation. The motors and cardan drive shafts are
slung off-centre at an angle to the driven axle because of the need to
clear the negative conductor rail during the transition phase when old
stock is still running.

Power requirement for each of the 24 traction motors would lie between
50 and 70 kW, depending on the performance requirement."

More in
http://www.railwaygazette.com/nc/new...-capacity.html

It certainly is revolutionary compared to anything we've yet seen on LU,
and probably more so than anything likely any time soon. They were
already aware of the looming PPP, but probably hadn't anticipated just
how devastating it would be.