linesider

noun

1. A fish, the striped bass.

   “These were chunky, feisty linesiders; most were between 20 and 24 inches.”

2. A person by the lineside, often for the purpose of observing and photographing trains.

   “RAIB will be looking at how train operations are managed in adverse weather. It will also examine how the railway manages information from members of the public that relates to railway safety. This follows reports that a linesider telephoned the railway to warn of the fallen tree before the train struck it.”