The locomotive hunt

On Sunday 21 May 1944 thousands of Allied fighters took off over northern France, Belgium and western Germany with a single task: to destroy trains. According to the US Army Air Forces official history (Craven and Cate), 763 fighters of the Allied Expeditionary Air Force operated over the northern half of France, while some 500 fighters of the Eighth Air Force roamed over Germany, strafing and bombing locomotives, wagons and railway bridges. The operation was given a codename borrowed from Glenn Miller’s hit “Chattanooga Choo Choo” – a song about a train – and it was the first of a series of similar missions repeated many times before the day of the invasion.

The line found in war chronologies about the “intensification of Allied bombing of targets in France before D-Day” needs some refinement. The trend itself is described correctly: in the second half of May Allied air forces were indeed striking ever harder at the communications network behind the future front. What was distinctive about 21 May, however, was not bombing in the usual sense – American heavy bombers sent only about 150 aircraft over France that day, and those against the “reprisal weapon” sites under construction near the Channel at Siracourt and Mimoyecques – but a massed fighter attack on moving rail targets, not only in France but also in Belgium and deep inside the Reich. It marked a new stage in a campaign which since early spring had aimed to cut the future Normandy bridgehead off from German reinforcements.

The Transportation Plan in mid-May

Since March 1944 the Allied air forces had been carrying out the so-called Transportation Plan – the systematic destruction of marshalling yards, engine sheds and railway workshops in France and Belgium. The plan, based on the analyses of the scientist Solly Zuckerman and pressed by Eisenhower’s deputy, Air Chief Marshal Arthur Tedder, and by the tactical air commander, Air Chief Marshal Trafford Leigh-Mallory, provoked a fierce dispute over the winter and spring. It was opposed by the advocates of strategic bombing – Air Chief Marshal Arthur Harris and General Carl Spaatz – and by Winston Churchill, who feared mass casualties among French civilians. In the end General Dwight Eisenhower pushed the plan through, and from mid-April both strategic air forces were working for the invasion. By early May heavy and medium bombers were striking daily at rail junctions, airfields, coastal batteries and radar stations as part of the pre-invasion bombing, and the French paid a price for this campaign too, most bloodily in the raid on La Chapelle on the night of 20/21 April.

The staffs, however, were not satisfied with the results. According to the USAAF official history, by 19 May rail traffic in the west had fallen by less than a third – just to the level at which the plan’s supporters had expected the first disruption of military transport. On 20 May SHAEF intelligence reported that the bombing of junctions was not yet having the expected effect: the Germans repaired tracks and stations efficiently, often restoring through traffic within hours, and sent trains by roundabout routes. Military transports had priority, so it was mainly French and Belgian civilian traffic that dropped out of the timetables.

Fighters over the tracks

Fighters had strafed trains in France before. On the Channel coast this had long been done by the Typhoons and Mosquitoes of Air Marshal Arthur Coningham’s RAF Second Tactical Air Force, and American Thunderbolts returning from escort missions often dropped down over the railway lines. The headquarters of the US Strategic Air Forces viewed this with misgiving, however, because from the air a military train could not be told from a passenger train, and an accidental massacre of civilians was feared. When the Allies concluded that French passenger traffic on the threatened lines had in practice ceased, Leigh-Mallory on 20 May authorised massed fighter attacks on all moving trains. From then on, as the official history puts it, a practice hitherto pursued quietly was applied openly and on a large scale.

The first mission took place the next day. Over France the operation involved fighters of the Second Tactical Air Force, of Air Defence of Great Britain and of General Lewis Brereton’s US Ninth Air Force – 763 aircraft in all, according to Craven and Cate. Pilots circled over the railway lines in pairs and flights, looking for locomotive smoke; when they spotted a train they dived and raked the engine with machine guns and cannon: a holed boiler released a cloud of steam and the locomotive came to a halt on the line. Immobilised trains were finished off with bombs and, in time, with drop tanks released onto them and then set alight by gunfire.

At the same time General James Doolittle’s Eighth Air Force for the first time sent its escort fighters on an independent raid against the railways in Germany itself. According to the Eighth Air Force operational record, 617 aircraft took off – 145 Lightnings, 139 Thunderbolts and 333 Mustangs; the official history speaks, in round figures, of 500 fighters over the Reich. The Americans claimed attacks on 225 locomotives, of which they counted 91 as destroyed, and Thunderbolts bombed railway bridges in western Germany. The pilots also strafed airfields – the Mustangs claimed several dozen aircraft destroyed on the ground. The price was high: the Eighth Air Force lost 27 fighters that day, 15 of them Mustangs. Ground-attack pilots were especially exposed to anti-aircraft fire, of which there was no shortage around stations and important bridges, and flying at a few dozen metres left the pilot of a hit aircraft little chance. All these figures are pilots’ claims and contemporary tallies; the real losses of the German railways were probably different and can no longer be established precisely.

The “Chattanooga” missions were repeated right up to the invasion. On 25 May three fighter groups of the Ninth Air Force operated over the Rhineland and northern France, and more than 600 Eighth Air Force fighters strafed trains in Belgium and France; on 29 May 571 American fighters ranged as far as eastern Germany and occupied Poland, and on 2, 3 and 4 June the Ninth Air Force flew further raids over France. According to the official history, in the two weeks from 20 May fighters damaged some 475 locomotives and cut railway lines in 150 places.

The Seine bridges

The second complement to the Transportation Plan – and, as it turned out, the more important one – was the bridges. For a long time destroying a bridge from the air was thought almost impossible: steel spans were hard to hit, they were ringed with anti-aircraft guns, and a British railway expert estimated that each bridge over the Seine would need some 1,200 tons of bombs. Spaatz and Brereton argued for trying, citing experience in Italy, where destroying bridges had proved the most effective way of paralysing German supply. On 21 April rocket-armed Typhoons attacked several bridges in France and Belgium, and on 3 May Bernard Law Montgomery’s staff formally asked the airmen to destroy the crossings by which the Germans could move reinforcements into Normandy.

The breakthrough came on 7 May. Eight Ninth Air Force Thunderbolts each dropped two 1,000-pound bombs on the steel railway bridge over the Seine at Vernon and brought it down into the river. The same day Thunderbolts and B-26 Marauder medium bombers badly damaged the bridges at Oissel, Orival and Mantes. Leigh-Mallory, convinced that the tactical air forces could cope with the task, ordered on 10 May the destruction of the bridges over the Albert Canal and the Meuse – which incidentally reinforced the German belief that the landing would come in the Pas-de-Calais. Between 11 and 26 May Marauders and fighter-bombers cut the crossings at Herentals, Liège and Hasselt.

On 21 May, however, the Seine bridges were temporarily off limits – and deliberately so. SHAEF had prepared a plan to cut all the crossings of the Seine below Paris and of the Loire as far as Blois, but for the sake of secrecy it was decided to strike the Seine only shortly before the invasion and to leave the Loire bridges, which would point straight at Normandy, until D-Day itself. The ban was lifted on 24 May, and from 26 May the Seine bridges became the expeditionary air force’s top priority. In the last days of May Marauders, Thunderbolts, Lightnings and Typhoons struck day after day at the bridges at Le Manoir, Poissy, Juvisy, Maisons-Laffitte, Rouen, Conflans and Mantes. Because the routes across the Seine also led to the Pas-de-Calais, the Germans could not read from these attacks where the landing would come.

Railwaymen, repairs and victims

The attacks on trains hit a system that was already badly strained. During the occupation the French state railways, the SNCF, had lost – according to Allied estimates of the time – roughly a third of their locomotives, taken to the Reich for the Deutsche Reichsbahn, and coal, spare parts and staff were also short. The fighter attacks, however, made the greatest impression on the railwaymen themselves. Strafing a locomotive endangered above all the driver and the fireman, and according to the USAAF official history French engine crews began deserting their jobs en masse, especially once the fighters started setting immobilised trains on fire. The Germans had to man the most dangerous runs with their own railwaymen, and after 26 May they markedly reduced daytime traffic, even on lines that had not been cut. From then on trains ran mainly at night.

Some French railwaymen were at the same time active in the Resistance. The railway underground had long been passing information on transports to the British and carrying out sabotage – the so-called battle of the rails – and for the night of the invasion a plan for mass cutting of the tracks had been prepared to complement the air operations. The cost, meanwhile, was borne by the whole population living near junctions and bridges. When the Transportation Plan was being argued over in March 1944, advisers warned Churchill that it might cause between 80,000 and 160,000 casualties among the French and Belgians, about a quarter of them killed; the Prime Minister demanded that civilian deaths should not exceed 10,000 and told Tedder to keep him informed of the “result”. According to frequently cited estimates, between 1 April and 5 June 1944 the Allied bombing in preparation for the invasion killed about 10,000 French and Belgian civilians; the exact number is not known, and different tallies put it higher or lower. Fighter attacks on trains added casualties among railwaymen and passengers – even with reduced passenger traffic they could not be avoided.

The Germans responded with repairs. According to the USAAF official history they repaired marshalling yards and track “with admirable efficiency” and skilfully rerouted traffic around the worst-hit points; by 1 June the French rail network had not reached the state of collapse the Allies had hoped for, although the 45,000 tons of bombs earmarked for the junctions had long since been exceeded. The most important military transports were still getting through, but much other work, including the extension of the Atlantic Wall, had to stop for lack of transport.

Place in the war

The mission of 21 May was one of the last links in a campaign which since the spring of 1944 had been intended to turn north-western France into an area through which the Germans could not move their reserves quickly. In the same days the final decisions were being taken in England – Eisenhower had already set the date of the landing, and the commanders had presented their plans at the St Paul’s School briefing – and preparations for D-Day were entering their final phase. North of the Seine stood the strong Fifteenth Army, waiting for a landing in the Pas-de-Calais; if the bridges were down, moving it to Normandy would take a long time.

On the day of the invasion, 6 June, all the crossings of the Seine below Paris – according to the US official history, twelve railway bridges and fourteen road bridges – were impassable, and fighter-bombers made sure the Germans had no time to repair them. The Loire bridges were attacked only in the days of the invasion. German divisions summoned to Normandy in June travelled by rail only as far as distant stations and then marched, often at night, along roads strafed by Allied aircraft during the day. A report by the German Air Ministry of 13 June stated that the raids had caused a breakdown of traffic on all the main lines and that strategic movements of troops by rail were practically impossible as long as the attacks continued at such intensity.

The assessment of the different parts of the campaign remained disputed. Field Marshal Gerd von Rundstedt told his Allied interrogators after the war that strategic bombing had had little effect on the French railways until the end of July, whereas the German officer responsible for military transport in the west described the effects of the attacks, especially on bridges, as catastrophic. Post-war American analyses, as well as the head of the French railways, judged the destruction of bridges and the attacks on trains to have been more effective than the bombing of large junctions; one American evaluation board even concluded that some 70,000 tons of bombs dropped on French rail centres before the invasion could have been used elsewhere. Supporters of the Transportation Plan replied that it was precisely the destruction of workshops and yards that had deprived the Germans of the reserves with which they might have patched up the cut lines.

Whatever these disputes, the locomotive hunt became a permanent part of the repertoire of Allied tactical air power. The fighter-bombers that practised attacks on trains in May 1944 became, after the invasion, one of the main reasons why Field Marshal Erwin Rommel and his commanders could not move troops freely by day. The price of this superiority was the ruined towns and junctions of France and Belgium and thousands of civilian dead – victims who in France long remained overshadowed by the memory of liberation.