The 14:52 Edinburgh to Birmingham had not a working engine in the lead
car.  This made for a quieter than normal journey!  It was a Super Voyager
- the sort that can tilt, but (IMO) usually don't!

It lost about 5 minutes to Carlisle (having climbed out of the
Forth Glen and crossed Beatock) and then lost another 6 or 7 to Oxenholme
(crossing Shap).  By Warrington, it was just 4 down - I got off there. 
The train was packed, presenting the remaining engines with a hard task,
but it looked possible that it would get to Birmingham within a couple of
minutes late but only 80% power.

This suggests to me that the trains are being driven well below
operational capability.  I was led to believe that this almost never
happened, and that trains were normally driven more-or-less flat-out.

Maybe this is the way that reliability is achieved?

Lots of comments
	are welcome
		and needed

		From
			Me

On Tue, 09 Aug 2005 00:30:59 +0100, Unknown, Even to myself wrote:

> The 14:52 Edinb to Bham had not a working engine in the lead car.  It
> was a Super Voyager the sort that can tilt, but (IMO) usually don't!

They can only tilt in certain places, where devices called "balises"
have been installed. These communicate with the train and permit tilt. 


> This suggests to me that the trains are being driven well below
> operational capability.  I was led to believe that this almost never
> happened, and that trains were normally driven more-or-less flat-out.

A 221 has 3750hp for about 275t of train. 13.6hp per ton. In contrast an
HST (2+8) has 4500hp for about 410t = 11hp per ton. Back in th egood old
days, a 4-REP unit had 2920hp for about 175t (16.7) and would haul a
further 260t of trailer vehicles giving 435t (6.7). So, Super Voyagers
and Voyagers do pack quite a punch. Even with one engine missing, a 221
has much the same hp/ton as an HST.
-- 
http://gallery120232.fotopic.net/p9632762.html
(09 016 at London Waterloo, 14 Mar 1981)

Chris Tolley wrote:

> On Tue, 09 Aug 2005 00:30:59 +0100, Unknown, Even to myself wrote:
> 
>>The 14:52 Edinb to Bham had not a working engine in the lead car.  It
>>was a Super Voyager the sort that can tilt, but (IMO) usually don't!
> 
> They can only tilt in certain places, where devices called "balises"
> have been installed. These communicate with the train and permit tilt. 
> 
> 
>>This suggests to me that the trains are being driven well below
>>operational capability.  I was led to believe that this almost never
>>happened, and that trains were normally driven more-or-less flat-out.
> 
> A 221 has 3750hp for about 275t of train. 13.6hp per ton. In contrast an
> HST (2+8) has 4500hp for about 410t = 11hp per ton. Back in th egood old
> days, a 4-REP unit had 2920hp for about 175t (16.7) and would haul a
> further 260t of trailer vehicles giving 435t (6.7). So, Super Voyagers
> and Voyagers do pack quite a punch. Even with one engine missing, a 221
> has much the same hp/ton as an HST.


I can't help but feel that, with this much power, perhaps a sensible 
method for releiving the overcrowding would be to add an unpowered (= 
cheaper) trailer to the middle of each set.

Robin

On Tue, 09 Aug 2005 00:12:38 GMT someone who may be Chris Tolley
 wrote this:-


>They can only tilt in certain places, where devices called "balises"
>have been installed. These communicate with the train and permit tilt. 


I am not sure if these have been activated north of Crewe yet.


-- 
 David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
 I will always explain revoked keys, unless the UK government
 prevents me by using the RIP Act 2000.

On Tue, 09 Aug 2005 09:37:46 +0100, R.C. Payne wrote:


> I can't help but feel that, with this much power, perhaps a sensible 
> method for releiving the overcrowding would be to add an unpowered (= 
> cheaper) trailer to the middle of each set.


They wouldn't be *that much* cheaper. They would need to be specially
built to match the shape, and of course it would be interesting getting
an unpowered one to tilt in the middle of a 221.

-- 
http://gallery120232.fotopic.net/p9683785.html
(150 1xx at Castlefield (Manchester), 8 May 2000)

Chris Tolley wrote:

> On Tue, 09 Aug 2005 09:37:46 +0100, R.C. Payne wrote:
> 
> 
>>I can't help but feel that, with this much power, perhaps a sensible 
>>method for releiving the overcrowding would be to add an unpowered (= 
>>cheaper) trailer to the middle of each set.
> 
> 
> They wouldn't be *that much* cheaper. They would need to be specially
> built to match the shape, and of course it would be interesting getting
> an unpowered one to tilt in the middle of a 221.


Have they shut down the production line?  It's not that long since the 
last 222s were delivered, and I fail to see how one of those bodyshells 
wouldn't fit.  It might not be that much cheaper to manufacture, but I'd 
have thought it would be a lot cheaper to maintain and run.  Perhaps not 
suitable on tilting units, but perhaps on 220 and 222?

Robin

Unknown, Even to myself wrote:

> >
> This suggests to me that the trains are being driven well below
> operational capability.  I was led to believe that this almost never
> happened, and that trains were normally driven more-or-less flat-out.
>
> Maybe this is the way that reliability is achieved?
>
> Lots of comments
> 	are welcome
> 		and needed
>
> 		From
> 			Me


It is possible to keep time with an engine out on a Voyager and two
engines out on a 180. The difference is on a 180 a cross feed can keep
the air con working in the adjacent vehicles. On a 4 car 220 lose two
engines and you lose the service.

jon.porter1@lycosmax.co.uk wrote:


> It is possible to keep time with an engine out on a Voyager and two
> engines out on a 180.


Surely that's just down to how hard the units are diagrammed. I don't
believe that any train with 5 engines can run to the same speed
profile with only 4 of those engines working. They might make the same
top speed, but it will take them a lot longer to get there with 20%
less power.

-- 
                          Stevie D
    \\\\\       /////     Bringing dating agencies to the
   \\\\\\\__X__///////    common hedgehog since 2001 - "HedgeHugs"
___\\\\\\\'/ \'///////_____________________________________________

On Thu, 11 Aug 2005 00:31:41 +0100, Stevie D wrote:


> jon.porter1@lycosmax.co.uk wrote:
> 
>> It is possible to keep time with an engine out on a Voyager and two
>> engines out on a 180.
> 
> Surely that's just down to how hard the units are diagrammed. I don't
> believe that any train with 5 engines can run to the same speed
> profile with only 4 of those engines working. They might make the same
> top speed, but it will take them a lot longer to get there with 20%
> less power.


True, but there aren't any (are there?) Voyager diagrams entirely on
125mph track. So the Voyagers have something to spare anyway.
-- 
http://gallery120232.fotopic.net/p11938595.html
(37 131 at Derby, 13 Jun 1985)

Stevie D wrote:

> jon.porter1@lycosmax.co.uk wrote:
>
> > It is possible to keep time with an engine out on a Voyager and two
> > engines out on a 180.
>
> Surely that's just down to how hard the units are diagrammed. I don't
> believe that any train with 5 engines can run to the same speed
> profile with only 4 of those engines working. They might make the same
> top speed, but it will take them a lot longer to get there with 20%
> less power.
>
> --
>


Yes they can, the speed of acceleration is still attainable due to the
excess of power. The accelerative effort is subject to electrical or
transmission limitations , but the remaining engines use more fuel as
they use more of their capacity and the range is subsequently reduced
quite markedly. This often leads to earlier terminaions of diagrams.
Even if the timings were tighter they could keep time, they would
simply have to work harder and use more fuel in doing so. This is true
of 22x and 18X where 750hp higher power engines are the norm.

Chris Tolley wrote:


> A 221 has 3750hp for about 275t of train. 13.6hp per ton. In contrast an
> HST (2+8) has 4500hp for about 410t = 11hp per ton.

> days, a 4-REP unit had 2920hp for about 175t (16.7) and would haul a
> further 260t of trailer vehicles giving 435t (6.7).


You are not comparing like for like.

When you quote the gross installed engine hp of a diesel train, that is
the maximum the diesel engine/s can ever put out at the crankshaft.

When you quote that figure for an EMU that is the continuous rating,
and for DC EMU is dependant on line voltage, and short term ratings
used for point to point running are way higher. Even the one hour
rating is never reached - not even on old Rep schedules Waterloo to
Southampton non stop becuse of coasting.


--
Nick

On 11 Aug 2005 17:30:41 -0700, D7666 wrote:

> Chris Tolley wrote:
> 
>> A 221 has 3750hp for about 275t of train. 13.6hp per ton. In contrast an
>> HST (2+8) has 4500hp for about 410t = 11hp per ton.
>> a 4-REP unit had 2920hp for about 175t (16.7) and would haul a
>> further 260t of trailer vehicles giving 435t (6.7).
> You are not comparing like for like.

And you appear not to be reading the posting in context.


> When you quote the gross installed engine hp of a diesel train, that is
> the maximum the diesel engine/s can ever put out at the crankshaft.
> When you quote that figure for an EMU that is the continuous rating

The important comparison in my posting was Voyager v HST. Like for like.
The mention of REPs was only a passing thought, referring to my earlier
postings on the matter.
-- 
http://gallery120232.fotopic.net/p14486539.html (31 158 up in the air)

On Tue, 9 Aug 2005 10:04:42 UTC, David Hansen 
 wrote:

: On Tue, 09 Aug 2005 00:12:38 GMT someone who may be Chris Tolley
:  wrote this:-
: 
: >They can only tilt in certain places, where devices called "balises"
: >have been installed. These communicate with the train and permit tilt. 
: 
: I am not sure if these have been activated north of Crewe yet.

I've been told that Pendolinos tilt all the way from Carlisle south - 
do Voyagers use the same balises?

Ian

Chris Tolley wrote:


> The mention of REPs was only a passing thought, referring to my earlier
> postings on the matter.



Even so, it is badly mis-leading - the figures you have found for 221
and HST are  not comparable with the one quoted for Rep by a factor of
around half (or double depending on which way you look at it).


A Rep unit with one motor coach disabled is better for this thread,
which is about Voyagers with disabled engines.


--
Nick

I dunno if its true or not, but I'm sure a Virgin Driver told me ages
ago that the voyagers run with the engines only working to 75%
capacity, and if an engine drops out, the three remaining engines then
run up to 100% each.

He said that apart from fault indications in the cab, the Driver
wouldn't be aware that there was an engine missing...

What about 5-coach Super Voyagers? I presume they have five engines;
what capacity do they run at? Apologies if this has already been
mentioned!

On 12 Aug 2005 08:38:28 -0700, spam@microchipped.co.uk wrote:


>What about 5-coach Super Voyagers? I presume they have five engines;
>what capacity do they run at? Apologies if this has already been
>mentioned!


They're heavier, so probably about the same.

Neil

-- 
Neil Williams in Milton Keynes, UK
When replying please use neil at the above domain
'wensleydale' is a spam trap and is not read.

terzal wrote:

> I dunno if its true or not, but I'm sure a Virgin Driver told me ages
> ago that the voyagers run with the engines only working to 75%
> capacity, and if an engine drops out, the three remaining engines then
> run up to 100% each.
>
> He said that apart from fault indications in the cab, the Driver
> wouldn't be aware that there was an engine missing...


Correct, well in the ideal World anyway. The loss of an engine will
have effects on things other than timekeeping and unless it was
possible to restart the engine the control would be looking to swap
sets into the diagram as range reduces due to remaining engines having
to work harder. In addition various auxillaries would be reduced in the
power they were consuming.
A common misconception in these more "complex" times,is hp per tonne
being a good guide to accelerative performance. Each engine on a
Voyager has different things to do in addition to powering traction
motors so the output will vary and the various electrical systems on
board will ensure the TM's get power within a band of acceptance. Hence
the problems for passengers if more than one engine is lost. With a 180
and it's simpler electrical layout, the ability to cross feed power
means it can run with two out comfortably, make it to a suitable
termination point with three out, and can do so even with four out. In
the last case air con would suffer. But the train would not be stuck in
the middle of nowhere as the full potential of the engine could be used
as traction.

On 12 Aug 2005 08:56:13 GMT someone who may be "Ian Johnston"
 wrote this:-


>I've been told that Pendolinos tilt all the way from Carlisle south - 
>do Voyagers use the same balises?


That is a question which I would also be interested in an answer to.

My understanding is that the latter don't tilt quite as far as the
former and thus there may be a different speed limit in places.


-- 
 David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
 I will always explain revoked keys, unless the UK government
 prevents me by using the RIP Act 2000.

On 12 Aug 2005 02:56:22 -0700 someone who may be "D7666"
 wrote this:-


>Even so, it is badly mis-leading - the figures you have found for 221
>and HST are  not comparable with the one quoted for Rep by a factor of
>around half (or double depending on which way you look at it).


Though with modern control systems electrical components are worked
a lot harder in general use than they used to be. The old maxim of
assuming double the power was possible for say five minutes is no
longer valid.


-- 
 David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
 I will always explain revoked keys, unless the UK government
 prevents me by using the RIP Act 2000.

On Sat, 13 Aug 2005 09:19:13 +0100, David Hansen
 wrote:


>On 12 Aug 2005 08:56:13 GMT someone who may be "Ian Johnston"
> wrote this:-
>
>>I've been told that Pendolinos tilt all the way from Carlisle south - 
>>do Voyagers use the same balises?
>
>That is a question which I would also be interested in an answer to.


I took a Pendolino from Milton Keynes to Carlisle a month or so ago,
and it definitely wasn't tilting north of Preston.

Neil

-- 
Neil Williams in Milton Keynes, UK
When replying please use neil at the above domain
'wensleydale' is a spam trap and is not read.

David Hansen wrote:


> Though with modern control systems electrical components are worked
> a lot harder in general use than they used to be. The old maxim of
> assuming double the power was possible for say five minutes is no
> longer valid.


I have to dis-agree with you there.

If anything, the opposite is true, the control systems do not make the
electrical installation work harder in an EMU but actually limit it. If
you take the example of 375/377s, each traction pack is software
limited to 750 Amp but the pack rating is actually 2000 Amp (see
several previous uk.r posts on this matter) it is the software that
controls it to 3/8 of its output. Not only that, as the train formation
gets longer, the software caps power drawn further - so that 6/7/8 car
are limited to 3000 A 10/11/12 car to 4000 Amp for the wole train.

--
Nick

jon.porter1@lycosmax.co.uk wrote:


> Yes they can, the speed of acceleration is still attainable due to the
> excess of power.


Sorry if I'm being thick, but I don't understand this. If you have 5
engines working flat out, and then one of those engines stops working,
are you really saying that the other four will increase their power
output by 25% to compensate - but that they only do so when one engine
is down?

-- 
                          Stevie D
    \\\\\       /////     Bringing dating agencies to the
   \\\\\\\__X__///////    common hedgehog since 2001 - "HedgeHugs"
___\\\\\\\'/ \'///////_____________________________________________

"David Hansen"  wrote in message
news:a3brf19hjgp97ovmgp2egor63pm7o6lb7h@4ax.com...

> On 12 Aug 2005 08:56:13 GMT someone who may be "Ian Johnston"
>  wrote this:-
>
> >I've been told that Pendolinos tilt all the way from Carlisle south -
> >do Voyagers use the same balises?
>
> That is a question which I would also be interested in an answer to.
>
> My understanding is that the latter don't tilt quite as far as the
> former and thus there may be a different speed limit in places.
>

Voyagers tilt 6 degrees and Pendolinos tilt 8 degrees. They must use the
same balises - 221s are used in tilt mode south of Crewe for some Holyhead
services, and I'm sure they don't have separate balises down to Euston. The
January 2005 MR has a photograph of a differential speed board - 100 mph for
conventiuonal trains, 115 for 221s, and 125 for Pendolinos.

Peter

On 13 Aug 2005 02:15:28 -0700 someone who may be "D7666"
 wrote this:-


>I have to dis-agree with you there.


Perhaps I picked my words badly. With modern trains there is far
less of a difference between the continuous rating and the maximum
rating than there was with a traditional control system.


-- 
 David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
 I will always explain revoked keys, unless the UK government
 prevents me by using the RIP Act 2000.

"David Hansen"  wrote in message 
news:a3brf19hjgp97ovmgp2egor63pm7o6lb7h@4ax.com...

> On 12 Aug 2005 08:56:13 GMT someone who may be "Ian Johnston"
>  wrote this:-
>
>>I've been told that Pendolinos tilt all the way from Carlisle south -
>>do Voyagers use the same balises?
>
> That is a question which I would also be interested in an answer to.
>
> My understanding is that the latter don't tilt quite as far as the
> former and thus there may be a different speed limit in places.
>

I have recently done a few trips between Warrington to Carlisle on 220, 221 
and 390's.
The tilt on the 390's is noticeable only if you look for it, I think the 
system could not be bettered.
When travelling on the 221's I have looked and looked and could not tell if 
tilt was in operation. As I believe the 220 & 221 run to the same timings 
the tilt is really not required.
Quite a few words and no answer, sorry.
Put me on the list of those who would like to know....... Maybe I should 
shell out 54 for a week of Warrington to Carlisle again... not a bad 
bargain as it includes the S&C as well. (Freedom Of The North West 7 Day 
Rover)

KW


KW

David Hansen wrote:


> Perhaps I picked my words badly. With modern trains there is far
> less of a difference between the continuous rating and the maximum
> rating than there was with a traditional control system.



Again I have to dis-agree.

An example. Don't know if you follow European railways, but earlier
this year I wrote a series of articles for TODAYS RAILWAYS concerning
the present generation of three phase motored electric locos.

The Bombardier Traxx e-loco - something that had been suggested (albeit
perhaps not too seriously) for CTRL-DS but could equally find its way
their on future freight - has a continuous rating of 4200 kW, a long
term high rating of 5600 kW and a burst mode intermittent rating of
6400 kW. This version of Traxx has been adopted by SBB BLS DB as well
as several access operators leasing them from Angel for trans-Alpine
freight.

The reason they have these is *because* of the the lower continuous
rating, a long term usable rating 33% above continuous, and a burst
mode rating 50% above continuous. The same applies in dynamic braking
mode. It all comes down to cost, the rival Siemens ES64 types are 6400
kW continuous - carrying a lot more of expensive IGBT traction
convertors for short duration operation that is seldom used.

If there were an open access frieght operaot that really wanted to push
the issue of CTRL and tunnel through freight, I'd say this might be the
sort of machinery to go for, Traxx traction ratings are not a lot
different from a UK class 92, and there is a CoCo on offer although
none have been taken up yet, although the BoBo would be OK on a new
line like CTRL. Crash etc standards are already met with. All it needs
is tunnel safety systems, and that is not a blocking point, all the
e-loco makers already supply multi-railway system packages, and yellow
front ends for the UK. Even 750 V DC third rail is not hard to acheive
- the things are already four volts down to 1500 V DC so its just
another lifting chopper configuration.

--
Nick

> >>I've been told that Pendolinos tilt all the way from Carlisle south -
> >>do Voyagers use the same balises?
> >
> > That is a question which I would also be interested in an answer to.



AIUI same balises but each type of trains own on board equipment
interprets the signals appropriately for itself. I may be wrong, not a
field I am that familiar with.


--
Nick

On 13 Aug 2005 07:09:04 -0700 someone who may be "D7666"
 wrote this:-


>The reason they have these is *because* of the the lower continuous
>rating, a long term usable rating 33% above continuous, and a burst
>mode rating 50% above continuous. The same applies in dynamic braking
>mode. It all comes down to cost, the rival Siemens ES64 types are 6400
>kW continuous - carrying a lot more of expensive IGBT traction
>convertors for short duration operation that is seldom used.


We are talking about slightly different things, but your figures
above illustrate my point well. My point is that the short term
rating of modern locomotives is much less than the traditional 100%
extra typically found with old control systems. In the above case it
is only 50% and I have recollections of 30% in some cases.

Your point is that some equipment is deliberately run at less than
its rated maximum in order to prolong its life. I entirely agree
that this is done.


-- 
 David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
 I will always explain revoked keys, unless the UK government
 prevents me by using the RIP Act 2000.

Stevie D wrote:

> jon.porter1@lycosmax.co.uk wrote:
>
> > Yes they can, the speed of acceleration is still attainable due to the
> > excess of power.
>
> Sorry if I'm being thick, but I don't understand this. If you have 5
> engines working flat out, and then one of those engines stops working,
> are you really saying that the other four will increase their power
> output by 25% to compensate - but that they only do so when one engine
> is down?
>
>

The engines are NOT working flat out, that's the point. The 750 hp
available as the engine output is a lot more than is actually needed to
power the trains and all the auxillaries. The reserve is there in case
one or two engines is lost. When an engine is lost the other four (or
three) can take the additional loading but will work harder therefore
use more fuel. The equipment spread along the different units is where
the vulnerability occurs. In the 180 it is possible to move on one
engine provided it is next to or is a compressor equipped vehicle.
The Voyagers do not have the same level of redundancy in the air and
electrical systems and need to have more vehicles operational to reach
a termination point.  That is the reason why the 185s are specified as
DH instead of DE units. Lessons learned with both the 180 and 220/221
units were applied and the 180 style engine/transmission chosen because
the equipment layout and performance allows a 180 to recover it's
passengers to a safe location in the event of failures where a 22x
would have to await rescue.

On 14 Aug 2005 00:41:56 -0700, jon.porter1@lycosmax.co.uk wrote:


>The Voyagers do not have the same level of redundancy in the air and
>electrical systems and need to have more vehicles operational to reach
>a termination point.  That is the reason why the 185s are specified as
>DH instead of DE units.


Surely that is the reason why the 185 has the same equipment layout as
the 180, not why it is DH rather than DE?  Is there some reason why
you can't build a 100% redundant DEMU with all equipment duplicated on
every vehicle like the "classic" DH Sprinter?  I can't see why there
would be - and it could be made even more redundant by providing a
traction bus line.

If we want true redundancy, shouldn't we be going back to the Sprinter
design and duplicating everything so, as long as there's enough power
to move the set, you'll get there?

Neil

-- 
Neil Williams in Milton Keynes, UK
When replying please use neil at the above domain
'wensleydale' is a spam trap and is not read.

Neil Williams wrote:

> On 14 Aug 2005 00:41:56 -0700, jon.porter1@lycosmax.co.uk wrote:
>
> >The Voyagers do not have the same level of redundancy in the air and
> >electrical systems and need to have more vehicles operational to reach
> >a termination point.  That is the reason why the 185s are specified as
> >DH instead of DE units.
>
> Surely that is the reason why the 185 has the same equipment layout as
> the 180, not why it is DH rather than DE?  Is there some reason why
> you can't build a 100% redundant DEMU with all equipment duplicated on
> every vehicle like the "classic" DH Sprinter?  I can't see why there
> would be - 


Weight and space and money.

> On 14 Aug 2005 00:41:56 -0700, jon.porter1@lycosmax.co.uk wrote:

> >That is the reason why the 185s are specified as
> >DH instead of DE units.



Jon, somewhat unusually, you have lost me on this one.

I have to agree with Neils response. A DEMU *is* the one than can deal
better with sort of issue by means of a traction bus line connecting
all the engine-alternator sets together. You can't really connect the
power packs of a DH together in adjacent cars in any practical way. The
fact that a Voyager may not be able to deal with more than 1 car out is
a design omission affecting that type of unit, not something that is
inherent to DE units. If it is auxiliaries and air-con and stuff, and
not a traction issue, then again you simply have a common bus line in
the unit for that too.

I just do not see how the selection of transmission has got anything to
do with all this.

--
Nick

Weight,space and money. the engines drive auxillary alternators which
can cross feed. The hydraulic transmissions are lighter and take up
less space than the electric transmissions and their associated
equipment which have proved to be so vulnerable and expensive in
manhours. Interestingly a competing design for the 185 was offered by
Bombardier as a diesel electric, looking like a Voyagerised 170.
The layout of the 185 was selected by people with experience of both
180 and 22x maintenance and operation.
Much was made of the 180 casualty figures early on being lower than the
220/221. They are grouped much closer and now the 222 has dropped below
them all.  The telling figure is the one which indicates the time taken
to deal with a casualty. 180s fare very well in this respect since the
errant vehicle is switched out and the journey continues.

Neil Williams wrote:

> >The Voyagers do not have the same level of redundancy in the air and
> >electrical systems and need to have more vehicles operational to reach
> >a termination point.


Can Voyagers be rescued (and have the electrics powered) by the Virgin
Thunderbirds?  If they can then the loss of redundancy is partially
made up for by the ability to be easily/comfortably rescued.

pete

naked_draughtsman wrote:

> Neil Williams wrote:
> > >The Voyagers do not have the same level of redundancy in the air and
> > >electrical systems and need to have more vehicles operational to reach
> > >a termination point.
>
> Can Voyagers be rescued (and have the electrics powered) by the Virgin
> Thunderbirds?  If they can then the loss of redundancy is partially
> made up for by the ability to be easily/comfortably rescued.
>
> pete


They can be rescued by anything that can couple up to them either by
physical connection with the coupler or by an adaptor. So a 180 can
rescue a 22x for example although it could not power it. The failures
in such cases tend to be more complicated and prevent simply dragging
clear plus the Virgin 57s are always somewhere else, too few of them,
too wide a range to cover.  Virgin do base a loco at Laira with the sea
wall in mind, it has been used to rescue several services including our
own sleeper on one occasion.

In article ,
 wrote:


> ... When an engine is lost the other four (or
> three) can take the additional loading but will work harder therefore
> use more fuel. ...


This is because the dead engine's fuel tank is inaccessible to the
other engines, right?  I'm guessing that this is not because the
engines become horrendously less efficient at higher load but because
they now have to provide the same power output (at approximately the
same specific fuel consumption) from the contents of 4 or 3 fuel tanks
instead of 5 or 4.

Sam