From the book description on Goodreads:
On a dark November evening, Sir Wilfred Saxonby is travelling alone in the 5 o clock train from Cannon Street, in a locked compartment. The train slows and stops inside a tunnel; and by the time it emerges again minutes later, Sir Wilfred has been shot dead, his heart pierced by a single bullet. Suicide seems to be the answer, even though no reason can be found.
Originally published in 1936, Death in the Tunnel is one of the mystery novels that was re-issued as part of the British Library Crime Classics series. I was really looking forward to this, not just because it satisfied a task in this year's holiday scavenger hunt, but also because I was hoping to discover more great writers from the golden age of mystery writing.
Sadly, for me Death in the Tunnel fell short of that mark. The story started out great with a mysterious death on a train that seemed to occur just as the train passed through a tunnel, yet there were no witnesses, no motives, no suspects, and according to the chief investigator it looked like suicide. (Tho, why there would be such an elaborate investigation if this was a suicide is a question that is not really answered...)
Anyway, the leading detective starts to interview people close to the dead man and at some point draws another investigator into the case. Without spoiling too much of the plot, I'll come straight to the problem I had with the story - the two investigators are utterly useless idiots, who come up with one random theory after another and seem to be stumbling along in the proverbial dark until the very, very end of the book.
Seriously, I had to roll my eyes a lot at their assumptions so many times because they just were the least logical conclusions ever - and yet, we were supposed to believe that this was great detecting when it seemed they created most of the red herrings themselves instead of actually sifting through the relevant information.
Death in the Tunnel is one of those books that would make for a pleasant beach read or something to pass the time while waiting at the dentist's, but I found it really tiresome as an antidote to a craving for a delicious mystery.