* Five tankers derail
* Third spill for company in two months
* Shares fall 2.4 pct on TSX
CALGARY, Alberta, May 21 (Reuters) - Canadian Pacific Railway Ltd said that five tankers containing oil derailed on Tuesday morning near Jansen, Saskatchewan, and one of the cars spilled 575 barrels of crude (24,150 gallons), the largest of three spills for the company in two months.
Ed Greenberg, a spokesman for Canada's No.2 railway, said the cars containing Western Canadian crude were on an eastbound mixed-freight train. He said the oil has been contained at the site of the derailment.
The derailment, which is being investigated by Canada's Transportation Safety Board, comes after one of CP's trains derailed near Parkers Prairie, Minnesota, in late March, spilling 360 barrels of Canadian crude.
A second, 400-barrel spill came less than a week later when a train carrying crude tankers and other freight cars derailed in northern Ontario.
A boom in North American oil production has prompted a huge rise in crude-by-rail transport as output has outgrown the existing pipeline network. The spill may again prompt concerns about the environmental risks of shipping crude on railways.
Hunter Harrison, the railway's chief executive, said earlier this month that CP was investing in new technology to limit derailments on the company's rail network in Canada and the United States.
The company does not yet know when the line will be returned to service. Greenberg said trains can be rerouted around the derailment.
Jansen is 148 kilometers (92 miles) southeast of Saskatoon, Saskatchewan.
CP shares fell 2.4 percent to close at C$139.97 on the Toronto Stock Exchange on Tuesday.