Re: Austrac gets HI locos

[pcc@ocean.com.au (Les Brown)]

mauried@commslab.gov.au (Maurie Daly) wrote in aus.rail:

>There are some inconsistancies across Australia in how locos are and are not 
>restricted between the various systems , and this was brought out in 
>submissions to the Reps standing Commitee on Rail reform.
>For example across the TAR and on the CAR and in SA where we have 47 kg/m rail 
>NRs are allowed 115 km /h , whereas in Victoria where we have 54 & 60 kg/m 
>rail NRs are only allowed 100 km/h.
>Melb to Albury is now laid with a mixture of 47 & 60 kg/m rail yet the speed 
>limits and loads on the 47 is the same as the 60 , same as the new line from 
>Newport to Nth Geelong C.
>
>The obvious question is whats differant between HIs 60 kg/m rail and the SRAs 
>or the PTCs to make such a huge differance.
>Is all the track in the US where 30 tonne axle load locos run 60 kg/m.
>Makes you wonder a bit?

I think it's because track standard is more than rail weights. Things
to be considered are sleeper spacing, ballast type and depth and how
level the "top" is.

When the LNER A4 Mallard ran it's speed test in 1938, not only was the
motion damaged in the process but also the permenant way. I heard that
the track was so badly deranged afterwards that it was deemed unsafe.
The rail was probably no more that 50kg/m bull-head rail, but all
other factors; sleeper spacing, etc, were probably all first class.
The loco had almost the same weight as an R-class and I assume (risky
stuff) almost the same axle-load at 19.5 tons, although probably
higher because a high-speed slip would have reduced the motion to
little more than twisted scrap. With drivers of over 2 metres, the
extra weight would have been needed during starts.

Probably the PTC's sleeper spacing and ballast is not as good as in
NSW or USA,  The PTC's spacings (according to my Jane's 1976) were
2,400 sleepers to the mile (stm) whereas TAR was 2,720 stm and NSW
2,640 stm. Hammersley was at almost 3,250 stm on 67 Kg/m rail.

Sorry for mixing imperial and metric, but the comparisons should still
be valid.

Les Brown