In February 1942, Heavy Artillery Unit (E) 672 reorganised and went on the march, and "Schwerer Gustav" began its long ride to Crimea. The train carrying the gun was of 25 cars, a total length of 1.5 kilometres (0.9 mi). The gun reached the Perekop Isthmus in early March 1942, where it was held until early April. The Germans built a special railway spur line to the Simferopol-Sevastopol railway north of the target. At the end of the spur, they built four semi-circular tracks especially for the Gustav to traverse. Outer tracks were required for the cranes that assembled Gustav.