The North British Railway had supported the first part of the West Highland Railway for commercial reasons, but it was now concerned that it would be expected to pick up the loss of the Mallaig extension, and it considered a loss to be inevitable. Nonetheless commitments had been given, and on 28 April 1892 the NBR agreed to work the extension of 50% of gross receipts, and that it would continue to support the line when the Government guarantee of 3% on capital over 25 or 30 years expired.