The situation in the flooded areas of Switzerland has begun to stabilise and had even eased in some parts of the country by Wednesday morning.
But it was still described as precarious in some regions, particularly in canton Bern, central Switzerland and canton Graubünden.
Officials say at least four people have died and two women are still missing after the torrential rains that swept parts of the country beginning at the weekend.
The body of a man was also found in Lake Walen but it is not clear if there is a connection with the flooding.
Thousands of people have had to be evacuated from their homes.
The BLS Lötschberg Railway managed to open the north-south line leading to the Lötschberg tunnel early on Wednesday morning but the rail situation elsewhere in the country has hardly changed, with the Gotthard line to Italy still closed.
There were still said to be huge problems with the consequences of the floods in the Bernese Oberland, Thun and the city of Bern's Matte area, with no electricity in either the Matte or the Felsenau district, which lie next to the River Aare.
Dead and missing
Rescue officials on Tuesday recovered two bodies in the small town of Brienz in the Bernese Oberland and the village of Dürnten in the Zurich Oberland region.
The victims were killed when a building collapsed while another person was found drowned in a swollen stream.
Police said two other people are reported missing, feared dead, in mudslides and flooding following some of the heaviest rainfall on record in Switzerland.
On Sunday two firefighters died near Lucerne when they tried to help evacuate a farm.
Water levels of rivers and lakes across much of Switzerland remained high, but the situation appeared to stabilise in some regions as the weather improved slightly.
However, many rivers burst their banks and lakes reached record levels, flooding parts of the capital Bern as well as the city of Lucerne.
Many villages and mountain valleys in the disaster regions, notably in central and eastern Switzerland, are sealed off.
Some 1,500 tourists are trapped in the mountain resort of Engelberg and were being flown out by helicopter. Power supplies were interrupted and telephone lines only worked intermittently.
Drinking water was contaminated in several parts of Switzerland.
Dozens of roads and rail links remain closed. The armed forces sent about 1,000 soldiers to the crisis regions to support civilian rescue operations.
The authorities estimate the damage caused by the floods to total around SFr500 million ($391 million).
Neighbouring regions in southern Germany and in Austria were also hit by flooding and landslides.
swissinfo with agencies
Officials say at least four people have been killed and another two are missing in the worst flooding and landslides in Switzerland since 1999.
Thousands of people have been evacuated.
The damage is estimated at about SFr500 million ($391 million).
Flooding and landslides also hit other regions in Europe, notably southern Germany, Austria, the Czech Republic, Romania and Bulgaria.