"This RR Crossing To Be Closed For Repair" on the NYSW

This evening I drove over the crossing where Sicomac Rd. in Midland Park crosses the NYS&W main, and there was a big sign that said the crossing was going to be closed for repair on or about 7/14/14. Is this a one-time thing or are all the crossings being looked at? I'd say the Newtown Rd crossing is worse than the Sicomac Ave crossing, and probably gets way more traffic.

They've been repairing all the crossings it seems over the last 4 years or so. Maybe they will be doing the other you mention once this one is done.

Well... you were indeed correct. The sign must've gone up some time early Wednesday morning, because it was there when I left for work. Unless of course I'm seriously blind and I just missed it Tuesday night. Either way, it's there - the Newtown Rd. crossing closes for repair on 7/7/14.

What are they doing with the trains while the main is closed for these repairs? Detouring?

No. They've been able to do all the repairs while keeping a normal train schedule. If anything the local trains maybe get bumped to overnights or something.

They need to replace the one in Hale Eddy, it's brutal!!!

They may be working their way up for all I know; seems like all the big ones in my area are getting repaired. The one right here by my house, they cut out the rails, put in those concrete-block grade crossings in, and then welded new rail in. Rails must have gone back in some time today, because this morning when I left for work they were still out. I don't have a picture of the rails out, but I do have a shot of the site right before the rails were cut out.
A local came down from the direction of Binghamton about 11:30, so the rails are back in service already.

It looks like the Goffle Road/Wyckoff Ave crossing is next - 7/24.