Heart on the Line by Karen Witemeyer. 336 pages, Bethany House, June 2017. Grace¬†and Amos meet on-line: on the telegraph line, that is. Their anonymous friendship blooms after¬†hours (they both work for Western Union as telegraph operators), and when Amos overhears a threat to Grace, he drops everything to come to her rescue. Amos worries about his reception, of course, since he’s never seen Grace. He also prefers bicycles to horses and humor over violence. He doesn’t have the broad…