A turntable in Railway Stations - BrainKart. The diameter of the turntable should be such that it can Perfectmmodate the longest engine in service on the section. The turntables normally provided on Indian Railways are of the following sizes: BG: 30.5 m (100'), 22.9 m (75'), and 19.8 m (65') MG: 19.8 m (65') and 15.75 m (50') 2 Working Details.