Complex sentence: Hertfordshire Rail Tours organised a charter of their Blue Pullman train up from London Kings Cross, whilst a further SRPS organised train travelled down starting from the Scottish town of Linlithgow, then proceeding via Edinburgh and the East Coast Main Line.
Split into simpler sentences: Hertfordshire Rail Tours organised a charter of their Blue Pullman train up from London King's Cross. A train organised by the Scottish Railway Preservation Society (SRPS) travelled down starting from the Scottish town of Linlithgow, then proceeding via Edinburgh and the East Coast Main Line.