[ghobs91]

For new infrastructure specifically, it costs a ton in the US because of a combination of non-transparent bidding system from contractors (politicians give their buddies bloated contracts) and construction unions overstaffing construction sites.

In other words, taxpayer money is being taken for a ride. For a good example of the latter situation, look up the rampant overtime abuse that's been discovered at the LIRR. There's little incentive to keep costs down and use funds efficiently, because it's tax payer money.