On US routes when get a red signal and contact the signaler. You get proceed at restricted speed. What is the the restricted speed though . Thanks.
In the U.S., restricted speed is legally defined under Title 49 Code of Federal Regulations (CFR) § 236.812 as a speed that permits stopping within one-half the range of vision, but does not exceed 20 mph
Different Railroads can set their own restricted speeds as long as they do not exceed 20 mph -- several have 15 mph so your approach is well founded.