* Highway 75 closed 35 days in 2009 flood year
* CN, CP lines stay open, BNSF closes some track in US
* Enbridge, TransCanada pipelines not affected (Adds comment from pipeline companies)
By Rod Nickel
WINNIPEG, Manitoba, April 18 (Reuters) - The main highway between North Dakota and the flooded Canadian province of Manitoba was set to close on Monday, but two rail lines remained open as the province prepared for the Red River's second-highest levels on record.
Highway 75 will close on Monday afternoon, the provincial government said. In 2009, when the Red River flooded at a comparable level, the highway stayed closed for 35 days.
A detour will likely add 100 kilometers (62 miles) to a trip from the provincial capital Winnipeg to the United States, said Geoff Sine, manager of the Manitoba Trucking Association.
That will cost about C$1.5 million (US$1.54 million) per week for the trucking industry, which wants to see a permanent solution to chronic flood problems, Sine said.
The highway is one of the busiest in Manitoba, carrying some 1,100 trucks a day.
The main freight carrier in North Dakota, BNSF Railway [BNISF.UL] had four lines out of service on Monday due to flooding, the railway said.
All three railways are important carriers of the Red River Valley's crops, which include spring wheat and durum, although grain shipments are not very active at this time of year.
Enbridge Inc (ENB.TO), whose pipelines carry as much as two million barrels of oil a day through Alberta, Saskatchewan, and Manitoba, said operations had not been affected, although spokeswoman Jennifer Varey said the company was watching the situation closely.
TransCanada Corp (TRP.TO), operator of the country's natural gas mainline and Keystone oil pipeline, said those facilities had not experienced any impact.
The Red, which flows north into Manitoba's Lake Winnipeg from North Dakota and Minnesota, is forecast to crest in Winnipeg around the end of April, the same time as the Assiniboine River, another major river that joins the Red.
Melting snow on top of saturated ground is causing flooding in Manitoba, with ice jams adding to the problem.
Winnipeg, a city of 633,000 people, is mostly protected with an engineered floodway that diverts some of the Red's excess water away. Flooding across southern Manitoba this year has taken in a record-large area, forced hundreds of people to leave their homes and closed hundreds of roads.
The Red has already crested at most points in the United States.
Wet fields in Manitoba, Saskatchewan and Alberta are expected to delay farmer planting by 10 days to three weeks. [ID:nN18296229] (Additional reporting by Jeffrey Jones in Calgary; editing by Janet Guttsman)