4:50 From Paddington

"Having done her Christmas shopping, Mrs. McGillicuddy relaxes happily in a train. Then another train, going in the same direction, draws abreast and for some minutes the two trains proceed side by side...... In the first class carriage of the second train, Mrs. McGillicuddy sees, to her horror, a man strangling a woman...."

Another Christie- an inoffensive murder mystery featuring Miss Marple.  This has some decent characters in it and for a change all the clues are laid out so it can be solved by the reader rather than her normal outrageous cheating.

Always a pleasant way to spend a lazy Sunday.