Harrow, London, England: 8 October, 1952. One of the most mysterious railway disasters leaves over 100 dead and Harrow and Wealdstone Station in complete chaos.

The 7.31 from Tring

It started out as a normal autumn day, with mist and fog over northwest London delaying trains which were running under fog signalling procedures.

Just before 8am the signalman at Harrow accepted the 10.20pm train from Glasgow. Once it was accepted by the signalbox at North Wembley, the Harrow signalman cleared all the fast line signals for it.

A few minutes later, he accepted the 7.31 suburban train from Tring on the slow line from the signalbox at Hatch End. By a quirk of fate, this train was carrying many workers from the railway offices at Euston.

By this time, the fog had thinned sufficiently for standard signalling procedures to be safely resumed. Once the Glasgow train had passed at 8.11, he replaced the fast line signals to danger and the distance to caution and was able to accept the 8.15pm overnight sleeper from Perth on the fast line. The Perth train had been delayed at Crewe and was over half an hour late. The Harrow signalman decided to run the 7.31 ahead of it. He set the crossover to send the 7.31 onto the Up Fast Line as scheduled.

The 7.31 was due in at 8.11, but was running a few minutes late and arrived in the station at 8.17. It was a nine coach train hauled by a 2-6-4 tank engine. The train was longer than standard suburban trains and was packed to the point that the guard had to let some of the boarding passengers stand in the Guard sections of the end coaches.

As the guard watched the loading, he prepared to give the driver the all clear. He suddenly became aware that there was an express approaching at high speed on the line currently occupied by the suburban train.

The Harrowing Events

The Perth train, hauled by one of the most powerful engines in the country, Princess Coronation class No 46242 City of Glasgow, passed through two signals set at danger and slammed into the back of the suburban's coaches. The impact punched a two-and-a-half inch depression into the track at the collision point and shattered the rear three coaches of the 7.31. The City of Glasgow veered to its right and almost immediately there was a second collision.

While the trains were approaching Harrow the signalman had accepted the 8am Euston to Liverpool express. This was hauled by two engines, Jubilee class 4-6-0 No 45637 Windward Islands and newly-overhauled Ex-Turbomotive No 46202 Princess Anne. As the first collision occurred, the 15-coach train approached Harrow from the south at nearly 60mph and had passed the signal protecting the platforms.

Horrified onlookers ran for cover as Windward Islands hit City of Glasgow almost head on and reared up over it. The engine punched through the station footbridge followed by Princess Anne and overturned across the Down Fast platform and the Up Local electric line. Coaches from the three trains now lay in a mangled mess of wood and metal.

Rescue

Rescue services arrived quickly including a medical team from a nearby US Forces base. Casualties were high, with 112 people killed, over 150 people injured and more than 80 of those seriously injured.

Despite the number of fatalities, rescuers were thankful that fire hadn't started in the wreckage; if it had, the death toll would have been much higher.

In terms of the number of casualties, Harrow was one of the worst accidents in Britain. Some casualties were mere bystanders, who were standing on the platforms or crossing the footbridge. A roll call of railway offices at Euston showed that some departments had been wiped out. The wreckage took several days to clear up, taking four days to reopen the fast lines. Windward Islands and Princess Anne were both scrapped, although City Of Glasgow was repaired and returned to service.

What Went Wrong?

This cannot be answered satisfactorily. One thing that was certain was that the Perth express failed to slow down and stop at the signals after passing the distant signal which was at caution. It was impossible to establish why the Perth train hadn't stopped because the driver and fireman had been killed outright.

Had the driver missed the distance signal? Had the morning sun shone in his eyes? Was the crew asleep or distracted by some footplate catastrophe? All that is known is that a full application of the brakes was made at the last minute, but it was too late.

ATC and AWS

The Chief Inspecting Officer of Railways, who chaired the Harrow Inquiry, recommended the further development and adoption of what was then called Automatic Train Control (ATC), now known as Automatic Warning System.

The Great Western Railway had run trials with ATC as far back as 1906 and installed the system on most of its principal routes.

ATC used a ramp between the rails, located at the approach to distant signals, which engaged a shoe under the engine. If the signal was at caution, a warning horn sounded; if the driver failed to act, the brakes would be applied automatically.

After the accident, British Rail installed ATC on most of its principal routes.