We’re moving a branch to 286k and there’s a 60 ft steel girder at MP 42.7 with a 5° curve right at the west abutment… I’m weighing a ballast mat and longer ties plus 136RE vs doing backwall/approach slab rehab to smooth the modulus jump; anyone have results on which holds geometry after a winter, and whether you adjusted superelevation or guard rails to cut impact loads?
I’d rehab the backwall/approach slab at that 5° and build a graded modulus transition; mats with longer ties help, but I’ve watched them lose top after one freeze–thaw unless drainage’s perfect. Run cant 1/4–3/8 in under-balance through the abutment and tighten guard/check to AREMA mins for 136RE to blunt wheel hits and the “bridge dip.” If the outage allows, add under-tie pads the first 60–80 ft and recompact shoulders — did last winter’s heave start right at MP 42.7 or a car length back?
We’ve had better winter hold by shaving 1/4 in off the superelevation for the first panel at the west abutment and setting the guard rail head 1/16 in low with a 1:20 taper on the entry; it cut the thump and kept crosslevel within 1/8 in through thaw — @jthompson92 did you run the guard rail flush or drop it a hair?