🚀 go-pugleaf

In article <6ftn45da3i5j9rt630njgvife0lon078r1@4ax.com>, Charles Ellson
<charles@ellson.demon.co.uk> scribeth thus
>On Wed, 01 Jul 2009 23:51:02 +0100, PaulB <abc@xyz.com> wrote:
>
>>Phil W Lee wrote:
>>> Espen Koht <ehk20@cam.ac.uk> considered Wed, 01 Jul 2009 10:38:36
>>> +0100 the perfect time to write:
>>> 
>>>> In article <pyb*RgQKs@news.chiark.greenend.org.uk>,
>>>> Theo Markettos <theom+news@chiark.greenend.org.uk> wrote:
>>>>
>>>>> Since yesterday trains have been suspended between Cambridge and Ely 'due 
>to
>>>>> overhead line problems'.  Services were supposed to be getting back to
>>>>> normal this evening, but the details are a bit puzzling...
>>>>>
>>>>> Yesterday there was a replacement bus between Cambridge and Ely.  There was
>>>>> the implication that trains were running between Ely and King's Lynn.  But
>>>>> as the only electrical supply point north of Cambridge is at Milton
>>>>> (N.Camb), how were trains powered?  Since FCC is an entirely electric
>>>>> railway, dieselising isn't possible.  Or did NXEA lend them some DMUs? 
>>>>>
>>>>> Or was the whole lot bustituted?  Wasn't looking fun for those I arrived
>>>>> with in Cambridge in the evening peak.
>>>> Reports from an Ely - Cambridge commuter have been that the overhead 
>>>> line problem was due to 'sagging lines'. Initially no trains were 
>>>> running, but eventually the non-electric services restarted while the 
>>>> FCC services continued to be bus substituted.
>>> 
>>> It must have been the wrong kind of heat.
>>
>>Reminds of a children's book from x years ago showing the effect on 
>>telephone wires between poles in winter and summer.  Winter, taught, 
>>nearly horizontal - summer, sagging.  I thought those piles of weights 
>>on a pulley system at the uprights were designed to compensate for 
>>expansion and contraction.
>>
>They can only cope with a particular temperature range. If the
>temperature becomes very hot or very cold and the OHLE section is very
>long then it is possible for the weights to be pulled all the way up
>(twang!) in very cold weather or to rest on the bottom of the rack and
>de-tension the wire in very hot weather. In many (most?) cases the
>OHLE sections are sufficiently short enough that neither extreme is
>reached but a long section might suffer this problem if no adjustments
>are made between the seasons to allow for it.

Heath Robinson mode = on..

Couldn't they just have two sets of weights one at either end twice the
capacity then;?..
-- 
Tony Sayer