judgment formed under emergency

It is one thing to judge of a situation in cold abstraction; another thing to form a judgment on the spot. The movement of trains requires prompt action, and we cannot hold that, as a matter of law, Brown, in leaning forward to remove a pin which would have yielded to his effort, was guilty of negligence because he did not anticipate that his foot might slip and be caught in an open frog rail of which he had or could be charged with knowledge.