This non-revenue connection tunnel was the means of supplying rolling stock to line M3 from 1976 until it was completed to Kőbánya-Kispest and the adjacent new depot in 1980.
This rail link tunnel served as a means of supplying rolling stock along line M3 from 1976 until it was completed to connect with Kőbánya-Kispest and an adjacent terminal in 1980.