More on Bishop Austrans

[David Bromage <dbromage@omni.com.au>]

A presentation on the project was given at the Institution of Engineers,
Australia on Thursday 16 September at a combined meeting of the
Institution and the Chartered Institute of Transport. Presenters were
Bruce Sinclair and Philip Kilby.

Bruce Sinclair, Director of Bishop Austrans, presented a video showing
computer generated simulations of the proposed system and apologized for
it being rather promotional. 

The proposal uses fully automated passenger vehicles with tracks fully
segregated except at stations. Small vehicles carrying 9 passengers,
which could be coupled in tandem at peak periods, are proposed, with
speeds of up to 120 km/h, running at 3s headways, capable of climbing
gradients of 20% and turning 8m radius corners. For very dense routes,
the next size up would probably be a vehicle for 30 passengers.  

The system uses steel wheels running on narrow gauge steel rails. Wheels
are inclined at 25 degrees (dihedral) so that the plane of the wheels
passes through the centre of gravity of the vehicle. The rails used are
Z section beams. Grip wheels running on the underside of the top flange
of the Z ensure that the vehicle cannot derail. They also ensure
sufficient adhesion to enable 20% grades to be climbed, and assist in
braking. As the grip wheels prevent the use of normal railway or tramway
switching, stub end switches are to be used, throwing the complete
moving section from one track to the other. A working model of such a
switch has not yet been developed. Third rail current collection is
proposed.  

A test track is available at the Chullora facility, but the lease must
be vacated in 18 months. A lease has now been negotiated in the ACT for
a longer test track; ground breaking is expected in about 12 months and
commencement of testing in about 18 months. The Chullora track is
principally designed for refining all the mechanicals, including
self-steering bogies, speed on curves, tight turning radius, traction
system, basic controls, (possibly) active tilt, as well as safety
issues, which include crash testing. Vehicles have been tested at up to
9km/h on the test track (yes, NINE kilometres per hour).

Having been unable to obtain any space in the Australian Technology Park
at Redfern, they plan to set up a larger test facility in Canberra. The
facility would enable speeds of 100 km/h to be attained on the main
line, using curves with a radius of 250 m. A $14.3 million research and
development grant has been received from the Department of Industry,
Science and Resources. The test track would also have tourist potential.

Philip Kilby, of CSIRO, presented a computer simulation (RTSim) of the
system in operation. The simulation is written using Java, which has
been found to be adequate for this purpose. The computer simulation
allows 1.3s to detect a "brick wall" emergency, such as might occur if
the preceding vehicle instantaneously came to a halt. Thence an
emergency deceleration of 0.75 to 0.8g is used to bring the vehicles to
a stop without crashing into the vehicle in front.


Now for my comments.

For starters, Bishop Austrans was actually laughed out of Sydney. They
were actually refused space at the technology park.

120km/h with 3 second headways means a vehicle seperation of 100 metres. 

Running with 3 second headways, and the software taking 1.3s to detect a
"brick wall" emergency, leaves only 1.7 seconds to decellerate from
120km/h to 0. This means a decelleration of 19.6m/s/s, or 2g, avoid a
collision. That's way in excess of the claimed 0.75-0.8g. Even at 0.75g,
all the passengers would have to wear seat belts or be restricted to
rear facing seats.

Let's assume that an emergency stop is performed at 0.8g (7.84m/s/s).
>From 120km/h, this means the stopping time is 4.25s, which is in excess
of the proposed headways. This is on top of the 1.3s required to detect
a "brick wall" emergency. This then means a minimum headway of 5.5
seconds, not the 3 seconds as claimed.

And this is assuming that you never want to merge at junctions or
stations. Slotting one vehicle in between others means a minimum headway
of 11 seconds on the "main line", assuming that all vehicles are
travelling at 120km/h. If one is merging from a station, and assuming a
relatively fast acceleration to 120km/h, the headways become something
like 15 seconds, or 500m. If the vehicle at the station isn't ready to
go at precicsely the right moment, it will have to wait another 15 seconds.

Aside from this, I don't think that 0.75g acceleration/decelleration
would be allowed on safety grounds. 0.3g might be allowed, but this
pushes headways out to   25 seconds or 800m of seperation.

The whole thing strikes me as being a pipe dream. They make a lot of
comparisons between themselves and Transrapid. Nuff said.

Cheers
David