Mr. Richard Logue:

I can only speak from my experience in Great Britain where it would be around a period of 40 years. If you are looking at procurement of rolling stock, for instance, and I think the assumptions work here too, you assume a lifespan of 40 years but there is a diminishing return on investment, the older and more dilapidated the stock gets.

On the physical infrastructure, Mr. Stacpoole will be little bit closer to this one than me, but I would say it is usually in the period of around 30 to 40 years as well. Mr. Stacpoole should feel free to correct me on that point.