Re: D57 Class [was Re: 6029]

["Derick Wuen" <cullend@webone.com.au>]

Peter Reynell and his Dad Arthur once described to me a chase of one of the
last 57's on the south, and said that it outdistanced them and they were
doing 60mph, I think between Gunning and Yass. Like many high speed yarns
(e.g. 100mph by 38's) this may have been exaggerated..... errr.......
overestimated.

A rule of thumb is that "modern" steamers can run at "wheel diameter speed
plus 10%", where wheel diameter is quoted in inches. 38's could do 70mph on
69" drivers, not much sweat. 57's on 60" drivers should be good for more
than 60mph. Balancing on a 3 cylinder loco with cranks at 120 degrees should
be better over a wide speed range by comparison with 2 cylinder with natural
imbalance at 90 degrees offset by wheel counterweights optimised for normal
operating speeds.

A comment on 57 on Melbourne Express test..... a possible reason that
maximum speed was low was that they were able to maintain the timetable with
spectacular performance on hills.

Also, are we sure the operating maximum qiuoted at 45mph was not a
restiction of freight wagons?

I have experienced lots of 50mph + on 60 class, 55" drivers, and I'm sure
capable of more, except my job was to keep the speed (and wear and tear)
down when a driver or inspector was keen to go for a last fling.

Rob Kearey wrote in message <39336FC1.B3A6B81B@powerup.com.au>...
>keith malcolm wrote:
>
>> > > Notice "top speed is 55 Mph". How long does it take to get to top
>> > > speed?? (I am asking this as a true question as I do not know.)
>
>> Where does 55 mph come from? The books I have show a maximum speed of 40
>> mph(including official NSWGR books).
>
>I believe that was from me, pulled out of the mouldering recesses of my
>memory. I thought the 57's and 58's were limited to 40 mph on certain
>lighter sections of track, but 55 on the mainline. Whether they could do
>it without chewing up valve gear is another matter.
>
>Disclaimer: I could be entirely, utterly wrong. It wouldn't be the first
>time!
>
>> Dave Malcolm
>
>Rob K