Rail washers on steam locomotives?

[NW Mailing List]

You need more resistance to get better traction.  Think of trying
to ride your bike.  On a surface with a lot of resistance such as
pavement, you can easily propel your bike.  This is because when
the whell pushes on the pavement the wheel doesn't slip.  However,
on ice there is low resistance and the bike wheel will slip and
you will have very little traction.  So on ice you will go slower
for the same amount of effort.
You wish the rolling stock to roll as far as possible without
adding more power from the locomotive.  This means that you
want to have the least amount of resistance.  Think about a
hockey puck.  On ice with hardly any resistance it will go
a long way.  On pavement with its higher resistance it will
not go nearly as far even when you hit it with the same
amount of effort.
Putting sand on the rail makes the rail+sand be bumpier which
results in higher resistance.  (Pavement is bumpier than ice
and has higher resistance.)  This helps increase the traction
of the locomotive.  But the sand means that the rolling stock
will not roll as easily.  So if you wash the sand off the track
after the locomotive passes over it and before the rolling
stock passes over the same spot then you increase the locomotives
traction without hurting the rolling stocks ability to roll.
Toney

NW Mailing List wrote:

> Thanks for the feedback.

>

> Let me understand what I'm reading here: a little bit of sand helps the

drivers of the locomotive get traction, but that same sand increases rolling
resistance on the wheels of the cars following the locomotive? Which N&W
locos had rail-washers--was it just the Y's, or did the J's and A's have
them as well? (thanks for the answers--maybe next week I'll ask everybody
about "smoke consumers" and how they worked)

>

> Thanks,

>

> Mike Weeks

>

> -----Original Message-----

> From: nw-mailing-list-bounces at nwhs.org

> [mailto:nw-mailing-list-bounces at nwhs.org] On Behalf Of NW Mailing List Sent:

Monday, March 03, 2008 7:39 PM

> To: NW Mailing List

> Subject: Re: Rail washers on steam locomotives?

>

> I thought I recalled that someone asked about the function of pipes on the

lead trucks of DMIR locos a few days ago.  If not, well, another memory
problem strikes back.

>

> DM&IR used sanders mounted on the lead trucks of their 2-8-8-4s, 2-8-8-0s

and 2-8-8-2s, if photos are representative.  There was an auxilliary sandbox
on the pilot beam for supply.  There were no sanders to the first set of
drivers on the front engine, so this must have been a substitute. They don't
appear to be rail washers.

>

> Dave Stephenson

>

>

>

>

>

>

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-- 
Toney Minter         E-mail:tminter at nrao.edu
NRAO - Green Bank    Phone: +1 304 456 2275
1 Observatory Road   Fax:   +1 304 456 2170
PO Box 2             WWW:   www.gb.nrao.edu/~tminter
Green Bank WV 24944

"You've got to be very careful if you don't know
where you are going because you might not get
there." - Yogi Berra