Sorry I'm late to the party. In the future, you may need to know the Rockwell hardness of the steel. I am retiring after 50 plus years as a welder (AWS D1.1-88 certified). Before going into business. I worked at a phosphate terminal in the port of Tampa. We ran into a situation where we had welds cracking in steel that was 8" thick. Had to send a piece to a lab and found it had come from a rock crusher with a rockwell of 60 in the first 3/8" of surface. Solution: Preheat to 400 degrees, checking with a Tempil stick, welding with E8018, multiple passes, and bringing the temp down for several hours. Took several shifts to accomplish. This was for the hubs of sprockets (two) that moved up to 3,000 tons of phosphate an hour onto ships. Railroad rails, if for structural loads, will be similar.