The Globe and Mail reports in its Monday, June 12, edition that set to come into effect with Ottawa's federal budget bill is an obscure law that has Canada's two main railways fighting back over concerns about expenses and congestion. A Canadian Press dispatch to The Globe reports that at the centre of the dispute is legislation that aims to expand what is known as extended interswitching. Interswitching refers to the transfer of cargo between two rail companies at a point where their tracks meet. Extended interswitching is when Company A must transport that cargo along its own tracks to a point where it meets Company B's rails, and it is currently required on request for distances of up to 30 kilometres. The practice seeks to spur competition, as someone shipping from a grain elevator on Canadian National Railway tracks, for example, could choose to have the freight transported by Canadian Pacific Kansas City instead if the price is better. The budget bill proposes a pilot that would extend the interswitching zone to 160 kilometres from 30 kilometres in the three prairie provinces for an 18-month period. CN and CP have gone on the offensive to warn of the deep harm they say it will inflict.