The coroner's jury did not equivocate. They blamed John Rowson, the pointsman on duty, for failing to reset the junction. But they used the same verdict to send a message to the railway company: the system itself, not just the man, was at fault. They recommended that Walton Junction adopt a new method of signalling and points. Rowson was charged with manslaughter in July 1867. He was a working man, employed to move heavy iron levers in a wooden cabin, expected to remember every train movement in his head and his pencil-marked register. The Birkenhead Railway expected human memory to do work that today would be done by automatic interlocking. When his memory failed, eight people died and he was sent to the assize court.

The Board of Trade enquiry made a recommendation that ended up shaping British railways for the next century and a half. Points, the enquiry said, must be interlocked with signals. A train should only be able to receive a clear signal into a section of track when the points along that section are physically and mechanically committed to the route the signal implies. If the points are set wrong, the signal cannot be cleared. If the signal is cleared, the points cannot be moved. The principle is so straightforward that it seems strange to learn there was a time when British railways did not work this way. Walton Junction in 1867 was one of the deaths that pushed the Board of Trade and Parliament toward making interlocking compulsory across the network. By the 1889 Regulation of Railways Act, it was.

Walton Junction did not survive long after the accident that made it famous. In the 1890s the Manchester Ship Canal was driven through Cheshire on its way to Manchester, and the canal builders needed to cross the Mersey south of Warrington. Rather than build separate bridges for the LNWR and the Birkenhead Railway, the engineers consolidated the two lines onto a single four-track bridge a little to the north of the original alignment. The old Walton Junction, where the 1867 collision had happened, no longer carried through trains. It became a stub serving a marshalling yard, then faded out of operational use altogether. Acton Grange Junction, where the new four-track bridge crossed the canal, took over. Today a flyer skirts the area south of Warrington Bank Quay station, and few of the cars on the M62 just to the north realise that the embankments they pass were once a busy main-line junction.

There are no memorials at the site of the Warrington rail crash. The names of the dead were recorded in the Times across four days in July 1867, and then mostly forgotten outside specialist railway histories. But the principle that came out of the enquiry, that points must lock with signals and signals with points, is still the foundation of every signal box, every relay interlocking, and every modern computer-based interlocking on the British network. Every time a passenger train rolls through a major junction in the United Kingdom without piling into the back of a slower one ahead, the mechanism that keeps it safe traces its ancestry, in part, to a pointsman named John Rowson who forgot to throw a lever on a summer morning a hundred and fifty-eight years ago.