Otto,
the switchback existed simply to get the DL&W to "downtown" Ithaca..
it came into Ithaca from Owego, but Ithaca is built on the side of a very steep hill..
the area up near Cornell University and Ithaca College is elevated quite a bit above downtown and "lake level"..
the hill was too steep for a straight rail line down the hillside, so they built a switchback to make the grade more manageable!
just like in the mountains..
The LV also had a line up "on the hill"..the former EC&N..
and the passenger mainline down at "lake level"..
(the LV tracks that are still there today..)
but the 2 LV lines in Ithaca were not directly connected in Ithaca..because of the hill..
they had to go all the way back south to VanEtten before they joined!
There was a plan to join the two LV lines at one point, by laying a cog railway down Cascidilla creek..the locomotive with the cog was ordered and delivered!
but the line was never built..
more here:
http://gold.mylargescale.com/scottychaos/leviathan.htm
but since this line was never built, the DL&W line was the only railroad connecting both "upper" and "lower" Ithaca..
thats all I know abotu the switchback..which isnt much.
anyone ever see any photos?
Scot