That is the money RSC spends on one route project according to RSC CEO Paul Jackson on the "Let's Talk Trains Show".
Paul Jackson wrote:We now spend about $250,000. In a couple of years the cost of developing a route will be upwards of $1M.
Right now, I get really dizzy. Never though it would be so much.

Source: http://forums.uktrainsim.com/viewtopic.php?f=314&t=124050