 The crossing was a part of the first one day round trip from London across the English Channel, which included a 2 hour 10 minute stopover for passengers in Boulogne..This crossing was considered to be the first one day round trip on this route.In June 1843, because of difficulties with Dover harbour, the South Eastern Railway company developed Boulogne-sur-Mer-Folkestone route as an alternative to Calais-Dover.