What sign should be placed at least 100 feet away during railcar operations?

The appropriate sign to place at least 100 feet away during railcar operations is the no smoking sign. This is due to the inherent risks associated with handling and transporting petroleum products, which are highly flammable. To prevent any potential ignition sources that could lead to catastrophic accidents, a no smoking sign effectively communicates the critical safety requirement of maintaining a smoke-free area near hazardous materials.

The significance of this precaution is underlined by the fact that railcars typically transport flammable liquids or gases, where even a small spark can result in a fire or explosion. The placement of this sign serves as a visual reminder to personnel and bystanders about the risks associated with the operation and the strict adherence to safety protocols that must be followed to ensure everyone’s safety.

While the other signs listed may be relevant in certain contexts, they do not carry the same immediacy or critical importance in relation to fire safety during railcar operations. Thus, the no smoking sign is the most important and appropriate choice.