TRAVEL.com ® Travel Forums - View Single Post

17th July 2008, 11:20 AM

"Andrew Robert Breen" <azb@aber.ac.uk> wrote in message
news:2s24l5x3t7.ln2@news.aber.ac.uk
> In article <1216301883.31232.0@proxy02.news.clara.net>,
> Recliner <nigelp@clara.co_dot_uk> wrote:
>> "Andrew Robert Breen" <azb@aber.ac.uk> wrote in message
>> news:j9l3l5xnbk.ln2@news.aber.ac.uk
>>> In article
>>> <a2ed70d2-c25d-4611-9080-9640b1080ec4@m3g2000hsc..com>,
>>> <thagor2008@> wrote:
>>>>
>>>> Why are new trains so much heavier? All they have over the old ones
>>>> is better crash protection and air con. Would those really make
>>>> that much difference to the overall weight? I can imagine it
>>>> adding on a few tons but not the huge excess we see in new stock.
>>>
>>> Why would you imagine that: consider that the typical weight of a
>>> family
>>> car has close on doubled over the last 35 years - almost all due to
>>> crash protection (with some down to NVH supression and some to a/c
>>> and such). The weight growth of trains looks very modest by
>>> comparison.
>>
>> Except that they've also (in some cases) switched to aluminium
>> monocoque construnction, which should make them lighter, just as it
>> has in cars such as the Jaguar XJ and XK. I have an XJ, and although
>> it's much bigger and has more gizmos than my previous BMW, it's also
>> a fair but lighter, and gets away with a smaller engine without loss
>> of performance. But the aluminium trains are heavier and use more
>> power than their steel predecessors.
>
> Hmmm..
>
> 1968 Jaguar XJ6 4.2: weight 1537 kg.
>
> 2008 Jaguar XJ-R: 1659 kg.
>
> Much less of a difference than with the F*rds (much less of a
> difference in NVH too, I'd suspect), but in spite of the XK
> boat-anchor in the old Jag and the new 'un's alloy structure, the
> old'un is still lighter.
>
> So: the aluminium cars are heavier and use more power than their steel
> predecessors...

Hardly -- if you're going to use the original 1968 car as the benchmark,
you can't compare it with the current XJR, which is a much faster car.
I'd expect the current 3 litre XJ to be both faster and lighter than the
original 4.2 litre XJ6 from 40 years ago. And that's before you consider
all the standard kit a modern Jag has that the old ones didn't (much
more advance, relatively speaking, than trains).

17th July 2008, 11:20 AM	#4 (permalink)
Recliner Guest Posts: n/a Classified Rating: % ()	Thameslink Rolling Stock "Andrew Robert Breen" <azb@aber.ac.uk> wrote in message news:2s24l5x3t7.ln2@news.aber.ac.uk > In article <1216301883.31232.0@proxy02.news.clara.net>, > Recliner <nigelp@clara.co_dot_uk> wrote: >> "Andrew Robert Breen" <azb@aber.ac.uk> wrote in message >> news:j9l3l5xnbk.ln2@news.aber.ac.uk >>> In article >>> <a2ed70d2-c25d-4611-9080-9640b1080ec4@m3g2000hsc..com>, >>> <thagor2008@> wrote: >>>> >>>> Why are new trains so much heavier? All they have over the old ones >>>> is better crash protection and air con. Would those really make >>>> that much difference to the overall weight? I can imagine it >>>> adding on a few tons but not the huge excess we see in new stock. >>> >>> Why would you imagine that: consider that the typical weight of a >>> family >>> car has close on doubled over the last 35 years - almost all due to >>> crash protection (with some down to NVH supression and some to a/c >>> and such). The weight growth of trains looks very modest by >>> comparison. >> >> Except that they've also (in some cases) switched to aluminium >> monocoque construnction, which should make them lighter, just as it >> has in cars such as the Jaguar XJ and XK. I have an XJ, and although >> it's much bigger and has more gizmos than my previous BMW, it's also >> a fair but lighter, and gets away with a smaller engine without loss >> of performance. But the aluminium trains are heavier and use more >> power than their steel predecessors. > > Hmmm.. > > 1968 Jaguar XJ6 4.2: weight 1537 kg. > > 2008 Jaguar XJ-R: 1659 kg. > > Much less of a difference than with the F*rds (much less of a > difference in NVH too, I'd suspect), but in spite of the XK > boat-anchor in the old Jag and the new 'un's alloy structure, the > old'un is still lighter. > > So: the aluminium cars are heavier and use more power than their steel > predecessors... Hardly -- if you're going to use the original 1968 car as the benchmark, you can't compare it with the current XJR, which is a much faster car. I'd expect the current 3 litre XJ to be both faster and lighter than the original 4.2 litre XJ6 from 40 years ago. And that's before you consider all the standard kit a modern Jag has that the old ones didn't (much more advance, relatively speaking, than trains).