Do trains have to cross diamonds slower, or how about diamonds that are not 90 degrees are those more prone to derailments?
Impact damage to the casting in the area across the gap is usually the limiting factor. Speeds rise with the use of OWLS type flange bearing frogs, at least in one direction. Trade-offs with the beatings that the frogs absorb as the angle gets more skew keeps speeds low with regular cast or rigid railbound frogs.
Truck hunting at the “gap” is kept to a minimum with long approach guardrails to the castings. Being that most crossing frogs are custom fabricaded with tangents and curves intersecting at random angles makes them horribly expensive, a chore to maintain and something to be avoided if possible. The pounding also takes its toll on the subgrade, making subgrade problems and cross-level issues a constant headache plus tie degradation happens faster. The mudmonster thrives in these places.
What MC said! Anyone who has watched the Rochelle cam over the years has seen most if not all of those issues, plus a lot of MOW work on the diamonds, including building up metal with welding and grinding. I’m not sure if other crossings are like Rochelle where there is an old crossing assembly in the weeds nearby, “just in case.”
The diamond at Durand, MI is an “OWLS,” or one-way low speed. The primary track is straight through with no gaps. The low speed side is lifted over the primary track, so lower speed is necessary.
The diamonds at Deshler are flange-bearing, both directions. The wheels don’t impact the gaps as the flanges are carrying the load, lifting the tread just off the rail. I believe the speeds in both directions at Deshler are 35 MPH.
If you watch the Deshler cam, you’ll hear impacts, but that is rail joints away from the diamond.
Do they have to … dunno. Do the rules say they’re supposed to … usually yes, if the railheads are on the same level. According to legend, MILW Hiawathas were supposed to slow to 90 mph at Rondout.
Once upon a time, the Erie/B&O (?) xing at Sterling, Ohio was famously acute – dunno what the speed limit was. It was somewhere around 40.9693N 81.8464W; the angle was 10-15 degrees?
From a 1944 B&O Akron Division Timetable
Eastward Passenger Trains 55 MPH
Westward Passenger Trains 45 MPH
Eastward Fast Freights 45 MPH
Westward Fast Freights 40 MPH
All other Freights 35 MPH
Why would the westward speeds be less than the eastward speeds?
I had hoped to be able to show a Google Earth picture of Sterling showing the alignments of the ERIE and the B&O that is now CSX. Only CSX exists these days and there are virtually no indications of where the ERIE had even existed.
The railroads ran parallell to each other for nearly a mile one either side of the the crossing which was done with the ERIE being on the North Side of the B&O East of the crossing and South of the B&O West of the crossing.