Set during war-time Germany.
Back says: "The Reingold Express roars on into the night. Gone now, in these dark early months of the war, are the tycoons and film stars, statesmen and spies who once packed its carriages. In their place the Reingold - the pride of pre-war Germany - carries an infinitely more precious cargo.
Gold. The entire reserves of the Bank of England, no less. Spriited away in a daring act of piracy masterminded by Hermann Goering in person.
It is an astonishing coup, and only an equally audacious and death-defying operation will ever restore the gold to its rightful place ... an operation which a team of raiders known only by their code-names are perfectly capable of pulling off, even if it means hijacking the Rheingold out of the heart of occupied Europe!"

Left on bookshelf.