"Roger H. Bennett" wrote in message ...
"Jack Taylor" wrote in message
...
Absolutely. The shortest formation for a CEP unit is 2-CEP (both driving
vehicles, which have cabs, pick-up shoes and are motored), whilst the
shortest formation for a CIG or VEP is 3-CIG/3-VEP, for the reasons that
you
give (driving trailers and a centre motored vehicle).

I don't know how it affects specific units, but the other thing nobody has
mentioned is the compressor and air reservoirs. If those aren't on the
driving vehicle, it's going nowhere, even with shoes, motors and a cab.

Roger

That's a good point, and it applies to batteries too. This
distribution of compressors and batteries is certainly commonplace on
London Underground trains. I heard that in the Camden Town derailment
the driving motor car which became detached and hit a wall was left
totally unlit because it had no batteries.

Thanks,

Dominic

Boltar wrote:

(Dominic) wrote in message . com...
Are the driving motor cars of modern DC EMUs such as Networkers,
Junipers, Electrostars and Desiros independent multiple units in this
way? It seems that no set is ever run without a pantograph trailer car
- is this because the motor cars rely on the electronics or other
systems in this car, even when running from the DC 3rd rail? Or can
the motor cars run seperately from the rest of the set?

AFAIK all the gubbins and even the motors are in the car that has the
pantograph whereas the cars at the front and the rear which although they
have no motors have the shoegear.

For DC Electrostar, you are comprehensively wrong.

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

Chris J Dixon wrote:

Boltar wrote:

(Dominic) wrote in message . com...
Are the driving motor cars of modern DC EMUs such as Networkers,
Junipers, Electrostars and Desiros independent multiple units in this
way? It seems that no set is ever run without a pantograph trailer car
- is this because the motor cars rely on the electronics or other
systems in this car, even when running from the DC 3rd rail? Or can
the motor cars run seperately from the rest of the set?

AFAIK all the gubbins and even the motors are in the car that has the
pantograph whereas the cars at the front and the rear which although they
have no motors have the shoegear.

For DC Electrostar, you are comprehensively wrong.

To explain a little mo, they are capable of being marshaled in
3, 4 or 5 car units. There is a simple reason why there is
always a PTOSL, as this is where the main power and control
cables routes cross over from one side to the other along the
length of the vehicle. If it was omitted, the inter-car jumpers
would not match. It also, on versions with retractable shoegear,
controls their air supply.

There is one motored bogie on each driving vehicle (DMOS), and
one on the MOS, There are none on the PTOSL

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

Chris Rogers wrote:
(Dominic) wrote in message
. com...
With an older DC EMU such as a 4-CEP I imagine that the driving motor
car can be uncoupled from the set and run independently under its own
power, and that 2 such cars could form a 2 car train.

This is not always the case with Mk1 EMUs - as I understand it, in
some units (like the 4-CIG IIRC) the driving cars are not the motor
cars - the units have separate driving trailers and a single motor
car. In this case, the 3rd Rail pickup shoes are on the
leading/trailing vehicles and not the motor car itself, so apart from
having no cab, an isolated motor car like this would have no power
supply.

However, in principle, I believe you are correct with some stock which
indeed has driving motor cars.

Are the driving motor cars of modern DC EMUs such as Networkers,
Junipers, Electrostars and Desiros independent multiple units in this
way? It seems that no set is ever run without a pantograph trailer
car - is this because the motor cars rely on the electronics or other
systems in this car, even when running from the DC 3rd rail? Or can
the motor cars run seperately from the rest of the set?

Modern stock introduces problems through a concept known as
'distributed systems'. The equipment required for the train to work is
not fitted exclusively on the driving or motor cars, but is
distributed along the length of the train. In this case, by removing
one or more cars from the set, some essential equipment would be
removed too.

In the case of Voyagers, you would expect that any formation of 2 or
more cars would be possible as each car has its own engine - in fact
because of distributed systems and other technical limitations, the
minimum consist of a unit is 4 cars.

I was told by a technician that in the case of Class 444/450 Desiros
that it is a very difficult procedure to separate cars in a set
anyway, because they are semi-permanently coupled and not designed to
be separated.

Hope this is of interest,

Chris.

P.S. This is written from my own, perhaps limited, knowledge and
understanding of the technical aspects. I am not from a railway
technical background, but believe this information to be correct. I am
sure more knowlegeable contributors will confirm or refute what I have
said.

Spot on!

Dominic wrote:
(Chris Rogers) wrote in message
. com...
(Dominic) wrote in message
. com...

In the case of Voyagers, you would expect that any formation of 2 or
more cars would be possible as each car has its own engine - in fact
because of distributed systems and other technical limitations, the
minimum consist of a unit is 4 cars.

That's interesting. I didn't know this inflexibility applied to
Voyagers. I thought distributed systems were less common on DMUs.
Maybe it's because of their 3-phase electric transmission?

Modern MU's have many systems that if placed in close proximity to each
other can affect performance, ie it is not a good idea to put OTMR
computers close to other stuff pumping out high levels of electrical
energy. The systems are distributed along the train in the same way that
the drive, be it hydraulic or electric is. Cross feeding between cars is
possible so that if one engine cuts out the coach is powered from the
others for ETS/HVAC purposes. It actually is not that inflexible. Modern
depots lifting equipment capable of lifting 5-10 cars at the same time.
By treating it as a unit and not a set of vehicles maintenance is easier
to plan.
The TMS systems in operation are only really effective over a maximum of
5 cars, so when coupling two sets the TMS on both must be able to talk
to the other one and gain information on all the systems by way of data
transfer, with this, the cross feeding etc, a lot of cables run between
the vehicles.
The TMS is usually in one of the outer vehicles behind the cab. Couple
two with the TMS at opposite ends to each other and there can be a few
seconds delay whilst the messages between computers match up and talk to
each other. In the early days of Voyagers 175s, and 180s drivers and
crews would be seen pushing buttons repeatedly after 5-6 seconds thereby
starting the system diagnostic over and over again. Mods to reduce the
complexity and display only the information the driver needs to see have
reduced this problem considerably. To test the viability of the TMS
several very long MU test trains have been run with up to 4 TMS's all
communicating along 20 vehicles. It worked.

Chris J Dixon wrote in message . ..
Boltar wrote:

(Dominic) wrote in message . com...
Are the driving motor cars of modern DC EMUs such as Networkers,
Junipers, Electrostars and Desiros independent multiple units in this
way? It seems that no set is ever run without a pantograph trailer car
- is this because the motor cars rely on the electronics or other
systems in this car, even when running from the DC 3rd rail? Or can
the motor cars run seperately from the rest of the set?

AFAIK all the gubbins and even the motors are in the car that has the
pantograph whereas the cars at the front and the rear which although they
have no motors have the shoegear.

For DC Electrostar, you are comprehensively wrong.

Yes , well DC only stock doesn't have pantographs does it so I suspect I
would be. And if you're going to state the bleeding obvious how about you
give a bit more info to the initial poster while you're at it.

B2003

In article , Dominic
wrote:

... There's a great history of the Networkers at
http://www.semg.org.uk/gallery/class465_1.html

There's a very fine description by Catford Loopy of how those trains
are put together at http://www.trainweb.org/seemus/. It's probably
more valuable for the current discussion.

Sam

Actually I'm wrong about the class 313s. They do have 2 driving motor
cars and not a central non-driving motor car.

May I point out that "modern Units" such as 313 can happily run without the
PTS - 313034 was used in this configuration in the late 80's early 90's when
its PTS was powering 316999 at clacton Depot(the networker testbed that was
ex class 210 DEMU vehicles ), I suspect that even 507/508 could also be run
the same

any DC Unit where the power equipment is housed in the DMS should be able to
run under their own power.
i seem to recall that the compressors are also housed in the DMS of
313/507/508 units

correct if im wrong by email please

kev

"Boltar" wrote in message
om...
Chris J Dixon wrote in message
. ..
Boltar wrote:

(Dominic) wrote in message
. com...
Are the driving motor cars of modern DC EMUs such as Networkers,
Junipers, Electrostars and Desiros independent multiple units in this
way? It seems that no set is ever run without a pantograph trailer
car
- is this because the motor cars rely on the electronics or other
systems in this car, even when running from the DC 3rd rail? Or can
the motor cars run seperately from the rest of the set?

AFAIK all the gubbins and even the motors are in the car that has the
pantograph whereas the cars at the front and the rear which although
they
have no motors have the shoegear.

For DC Electrostar, you are comprehensively wrong.

Yes , well DC only stock doesn't have pantographs does it so I suspect I
would be. And if you're going to state the bleeding obvious how about you
give a bit more info to the initial poster while you're at it.

B2003

In article , Dominic
writes
You're right - I think these units with a central non-driving motor
car started with the 4-CIGs and includes classes 313, 455 and 319.

Class 313 is two driving motors with shoes, separated by a pantograph
trailer.

The only other classes I know off by heart are those on my local line:
- 317 is two driving trailers separated by a pantograph motor and a
trailer, both non-driving;
- 365 is two driving motors separated by two non-driving trailers, one
with a pantograph. [They don't carry shoes round here.]

--
Clive D.W. Feather, writing for himself | Home:
Tel: +44 20 8495 6138 (work) | Web: http://www.davros.org
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Written on my laptop; please observe the Reply-To address