London's rail network covers 17 terminal stations and 20+ operators. Paris in 2h16m, Brussels in 2h01m, Birmingham in 1h17m. London to Paris emits only 22 kg CO₂ vs 244 kg by plane.
Valencia to Barcelona by train in as little as 3h05m with Euromed. Alvia tickets start from $44. Departs Valencia Joaquín Sorolla, arrives Barcelona Sants.
Vienna to Bratislava by train in about 1 hour on hourly REX6 services. One-way from €11, or €18 for a round-trip ticket including Bratislava city transit.
London to Rome by train takes 14–19 hours over 889 miles. No direct service — two changes required. Via Paris route: Eurostar then through Milan or Turin.