[1] Set in 1851, it is about a railway robbery which is investigated and ultimately solved by two Scotland Yard detectives, Inspector Robert Colbeck and Sergeant Victor Leeming.

Using duplicated Chubb safe keys, they steal all the mailbags and a consignment of over £3,000 in sovereigns being transferred from the Royal Mint to a bank in Birmingham.

The train driver, who tries to resist the robbers, is badly injured and his fireman is forced to drive the engine forward to where a section of track has been removed, causing a derailment.

Colbeck and Detective Sergeant Victor Leeming travel to Leighton Buzzard where they meet Inspector Rory McTurk of the railway police.

McTurk strongly resents their involvement but Colbeck and Leeming soon establish that members of the railway police were guilty of deserting their posts on the train in order to play cards, thus making it much easier for the gang to carry out the robbery.

He and Leeming begin enquiries at the organisations involved with the shipment: the L&NWR, the Post Office, the Royal Mint, the fictitious Spurling's Bank in Birmingham and the Chubb factory in Wolverhampton.

Although Tallis dismisses Colbeck's theory, it is valid as gang leader Sir Humphrey Gilzean has an obsessive hatred of railways.

Colbeck makes the connection and realises, despite more opposition from Tallis, that an attempt will be made to destroy the locomotives on display at the Great Exhibition.

Colbeck is right about the Crystal Palace and, aided by Leeming and Mulryne, is able to arrest Jukes and the Seymours one night when they try to destroy the Lord of the Isles.

Working on what little is known about the three prisoners, Colbeck and Leeming discover their common military background and make the link between them and two of their former officers who both left the Army on the same day.

Colbeck establishes that Gilzean has a pathological hatred of railways and even Tallis agrees that the case has been solved, so the investigation is now a manhunt but with Madeleine's life at stake.

Caleb Andrews drives for the L&NWR but his train was travelling on the route built by the London and Birmingham Railway (L&BR) and opened in 1838.

The Crystal Palace's construction materials, its cast iron framework and sheets of glass, were manufactured in Birmingham and Smethwick, so they were transported by rail through the Kilsby tunnel to London.

On his trip to Birmingham and Wolverhampton, Colbeck is disturbed by seeing the Black Country and afterwards tells Leeming that he now understands exactly what William Blake meant when he wrote about the "dark, satanic mills".

Colbeck is nevertheless intrigued by industry, especially the railways, and in conversations he refers to Edward Bury, Thomas Russell Crampton and Daniel Gooch as engineers and locomotive designers he especially admires.