In the novel 4.50 from Paddington, David West is the second son of Miss Marple’s nephew Raymond West. He works at British Railways. At the beginning of the novel, Miss Marple writes to David to ask which trains might pass the 4:50 from Paddington, as Elspeth McGillicuddy had observed.

David writes back to Miss Marple, telling her that the 4:33 or the 5 o'clock are the only two trains that might apply. The 4:33 is a slow train, and might be overtaken somewhere by the 4:50, although it is expected at Brackhampton five minutes earlier. The 5 o'clock is an express train, and passes the 4:50 just before Brackhampton. Mrs McGillicuddy had said that the carriage in which the murder took place was not a corridor one, which means that it was not an express train. From this, Miss Marple determines that the murder took place on the 4:33.

David suggests in his letter that Miss Marple wants this information because there is a village scandal of "a fruity character", such as her seeing the mayor's wife being embraced by the Sanitary Inspector. He also thanks her for the pullover she had sent him for Christmas.

Community content is available under CC-BY-SA unless otherwise noted.