🚀 go-pugleaf

In article <D5rDwp.410@ntmtv.com> adrian@ntmtv.com (Adrian Brandt) writes:

>I'd like to find out all about spring switches.  Where are they
>typically in use today?  What are the salient details of their
>deployment : reliability, longevity, safety, cost (initial and
>operating & maintenance), speed/weight limits, etc.

  I wish I had my system standards books here.  I can tell you that most of
the sidings on Santa Fe's original main line north of Albuquerque, NM have
spring switches.  This is single track territory.  I had a chance to see
a spring switch in action a few years ago, during a trip on Amtrak Train 4.
Our train was put in the siding at Lamy for #3.  The siding had to be
manually lined coming in, but thanks to the spring switch, we were able to
just roll out at the other end, without stopping, at about 20 mph.  Watching
from the rear vestibule, I was surprised at how long it took the switch to
recover and return to the normal position...about 7 seconds in fits and
starts.
  These switches look like normal high-star, double-headblock switchstands,
but instead of having a rigid throw rod (I think that's what it's called),
there is a big, enclosed spring joining the rod connected to the points
with the rod from the throw lever.  These switches can be locked and still
function as spring switches because the spring is an integral part of the
linkage.
  Santa Fe also uses Ramapo spring switches, which cannot be locked if they
are to be run through the "wrong" way.  Here, the springs are not an integal
part of the linkage.  I haven't seen one in action, but I believe that
when one is run through the wrong way, everything, including the throw
lever, swings over to the other position and stays there.  The springs
keep the switch from adopting a "half thrown" position, but do not move the
points back to the original alignment after the train has passed.  I've only
seen these switches used in yard-type settings...they're a little
impractical for siding switches where you want the switch to spring back to
"normal."  And too, you never know what the local kiddies might do when
presented with an unlocked switch.

--
 ,_,,___......____...____..------ ______________           _--____________--_
 _I      ````              I[|]I I      SANTA FE~~~~~~~~~, I @    I  I      I
 ~/---~~~~~~~~~~~~~~~\~~~~~\---'_I        2903           I IATSF  I\/I      I
/~o==o-( )-( )-( )-( )~~o==o~~~~~~o=o=o=o~~=====~~o=o=o=o~~~o==o~~~~~~~~o==o~
--Evan Werkema--elw4@po.cwru.edu--"Ship and Travel Santa Fe...All the Way!"--

Adrian Brandt (adrian@ntmtv.com) wrote:
: I'd like to find out all about spring switches.  Where are they
: typically in use today?  What are the salient details of their

There is a spring switch on the NWP, just north of Novato. It is at
the southern (well, western to SP) end of a scale track. All S/B trains
run through the scale, returning through the switch to the mainline.
There is a dwarf signal next to the switch, which is ALWAYS lit. This
signal is visable from hiway 101 (northbound). The only other signals I'm
aware of on the NWP are at the Petaluma river swing bridges, which are
normally dark. I don't know if there is a spring switch at the north end
of the siding, I haven't hiked out there yet.

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I didn't know that spring switches are such rarities, but EJ&E put one in
in Matteson (IL) when they pulled up their second main west of there.
The switch is lined for the south (eastbound) track.  Eastbound trains
are thus automatically routed on the correct track in double track
territory while westbounds can proceed off their track into the single
track main.  No one needs to stop.

I haven't gone out to see it in operation but the comment about the delay
is interesting.  I'm sure there must be some kind of dashpot mechanism.
You wouldn't want the points to snap back after every axle like on an HO
model switch.