Complex sentence: Thameslink was a train operating company in the United Kingdom, run by Govia (a joint venture between Go-Ahead Group and Keolis--previously Via-GTI, renamed following its acquisition by SNCF) operated the London commuter railway line known by the same name.
Split into simpler sentences: Thameslink was a train operating company in the United Kingdom, run by Govia (a joint venture between Go-Ahead Group and Keolis--previously Via-GTI, renamed following its acquisition by SNCF). It operated the London commuter railway line known by the same name.