Complex sentence: Speyer railway was opened on 17 July 1873 and it was extended to Speyer on 10 December 1873 over a pontoon bridge, which had been established for road traffic in 1865.
Split into simpler sentences: Speyer railway was opened on 17 July 1873. It was extended to Speyer on 10 December 1873 over a pontoon bridge that had been established for road traffic in 1865.