super-elevation technical questions

[NW Mailing List]

Typically, sidings up to train length were not superelevated due to the
restricted track speed (<15mph) of trains entering preparing to stop.  An
exception was a middle passing track with high-speed turnouts/crossovers on
each end that could be used as a crossover between mains.  Not to be
confused with middle storage tracks, some of which were former passing
tracks, that were maintained to the lower "slow" level or less (older ties
spaced farther apart in cinder ballast), typically with a trailing-point
turnout on each end (to the WB main on the west end and EB main on the east
end).  An example photo is in Ed King's "The A" p.85 or revised, p.95.

According to a table of maximum passenger train speed as a function of
curvature and elevation (ref. N&W standards plan L-318), the lowest speed
requiring superelevation was 20mph.

Turnouts on curved main track were avoided, but when necessary, were laid
(for outside turnouts) with custom-cut ties to laterally roll the diverging
track up over the superelevation and back down to grade.  You're handlaying
track, right?  An example photo is in Louis Newton's "Rails Remembered,
Vol. 4" p.874.

Signals were to clear a clearance template of 8' from track center
extending from top of rail up at least 12'.  I've measured bracket signal
tower bases on 44' centers across tangent double track which works out to
15', base center to track center (14' main line track centers).  Signal
heads were usually on 6' vertical intervals but height varied with head
number, style, and signal type.  N&W Signal Diagrams from the Commisary has
all kinds of dimensional details on signal construction and placement.

Grant Carpenter


> As I've probably bored you all before, I model the 1930's era.  I'm doing

the super-elevation aspects on my mainline, using balsa strips under the
outside rails and sanded down to level on the ends as the mainline
straightens out.  I guess John Armstrong would be proud.  

>

> My question has to do with sidings which parallel the mainline.   

> Do they also put super elevation on them?  

> Is super-elevation only done when the speeds on the  siding are above

some speed like 25 mph or so?  

>

> When a turnout is on a curve, and the siding is on the outside, It seems

logical that the spur would be super-elevated as the turnout would
technically need to be flat, so the spur would be at a higher level than
the mainline.

>

> Also, how far from the track centerline did they put the signals?  

> I'm using a combination of semaphores(scratchbuilt) and Intermediate

Block (Oregon) signals.  

> How high up did they put the bottom target, or semaphore on the poles?

>

>

>

> Mark Lindsey

> y3a at earthlin