The Whitleys from 51 and 78 Squadrons arrived at Ringway on the 15th January 1941, where they were converted to accommodate parachutists, equipment containers, and long range petrol tanks. The aircrews were rapidly trained in the art of dropping troops, and discovered, contrary to popular opinion in the RAF, that it was not at all similar to a bombing run with human ordnance. The weather conditions were poor, and neither aircrews nor parachutists were able to practice as much as they would have liked, yet a number of drops were carried out, during which "X" Troop focused on making rapid exits from the aircraft to ensure that they were not too widely dispersed on landing, and once on the ground they would form-up and gather in their supply containers with the utmost speed. It was during this training that a tragedy occurred on the 22nd January, when Bombardier Dennis drifted off course during a descent and drowned in a pond.
The security precautions surrounding Operation Colossus were extremely tight, and from the outset the men had been warned not to mention anything of what they were doing to anyone. To be sure that the order was obeyed, not only were their letters checked, but on the evening excursion to the local pub, their only contact with the outside world, security personnel were lurking nearby trying to pick up on their conversations. Not that there was much they could reveal because the nature of their objective and its location was kept secret from all but the officers until just a few hours before they were to attack it.
Even so it soon became quite obvious to everyone that they were to destroy some manner of bridge, as a plasticine model, accurately depicting such a structure as well as the Tragino river and the surrounding topography, was put on display in Group Captain Harvey's office for every man to carefully study and commit to memory. As they would inevitably speculate where this bridge was located, a few misleading hints were left lying around for them to discover, with maps of East Africa and photographs of bridges around Addis Ababa encouraging the prevailing view that they were bound for Abyssinia. A wooden replica of the bridge was assembled at Tatton Park for them to practice on, and it was kept under a 24 hour guard to prevent it from being seen by the public. During their exercises, "X" Troop would drop nearby, collect their heavy equipment containers and carry them to it, and were eventually capable of moving half a ton in just over 30 minutes.
The training also placed a heavy emphasis on physical fitness and shooting with pistols and sub-machine guns at night; both of which were expected to be key factors if they were to succeed in their mission and have any hope of rescue. Every day the men would complete a three mile run, followed by 30 minutes physical training, and a brisk fifteen mile march in two hours in full kit.
They also attended numerous lectures, and as it was highly likely that most if not all of the party would be captured, one of these was given by an officer of MI9; an organisation established to help prisoners of war to escape. A few of the officers and sergeants were made aware of a code system which could be incorporated into their letters home, enabling them to pass on any useful intelligence they came by. A variety of escape apparatus was also concealed in the clothing of every man; a small hacksaw blade was hidden above the left breast pocket of their battledress; two one foot square silk maps of northern and southern Italy could be found in the sleeves; their collar studs contained a small compass; and each man also had 50,000 lire sewn into either the collar or waistband, with the officers also being issued with ten gold sovereigns.
Towards the end of January, "X" Troop were joined by two middle aged outsiders who were to accompany them on the raid as translators; Flight Lieutenant Ralph Lucky and Fortunato Picchi. Lucky, a 43 year-old RAF officer who was fluent in Italian and several other languages, had been born in Bosnia where his father, an engineer of Montenegrin descent but born and raised in Britain, was working on railway construction. His real name was Raoul Lucovich, but he had acquired the nickname of Ralph Lucky whilst serving in the British Army in the First World War, during which he was awarded the Military Cross. Picchi was a year his junior and had also served in the First World War, but with the Italian Army. He had lived in Britain for 20 years, and had worked as head waiter at the Savoy Hotel before being recruited by the Special Operations Executive. There happened to be another Italian speaker in "X" Troop who was a legitimate member of the 11th SAS; Trooper Nicola Nastri, tactfully going by the pseudonym of John Tristan, who had been born in Italy but was raised from infancy in Britain.
The culmination of their training came on the 30th January, when a full scale dress rehearsal was carried out with a night drop on the replica bridge. The prevailing poor weather, however, conspired to reduce what was intended as a final confidence boost into an absolute shambles. The drop was made into a 30 mph wind which caused most to overshoot the target with a few being dragged across the ground as they struggled to collapse their chutes. One man came down on the roof of Tatton Hall, and several others were stranded in tall trees and had to suffer the indignity of being rescued by the local fire brigade. Fortunately no one was more than superficially hurt. The exercise had not been the resounding success that had been hoped for, but it did at least make it clear that the operation should only be carried out in favourable conditions.