GRIPES

[old man emu]

Yes. The cost of tunneling underneath the Blue Mountains would be astronomical. The problem is that the terrain rises sharply from the relatively flat Cumberland Plain on one side of the Hawkesbury  River to the steep rugged country at the opposite bank, and continues to rise about as far as Katoomba. Emu Plains at the start of  current road is 90 ft AMSL and Katoomba is 3335 ft AMSL. They are separated by 33 kms in a straight line. All the way from Penrith to Lithgow there are deep gorges and ridges which simply can't be lowered to fill the gorges. 

 

There is no direct line between Emu Plains and Lithgow that isn't affected by the same landscape. Because of the occupation of the land along the present road, it is virtually impossible to construct a multi-lane road all the way.