Even looking at Gotthard tunnel is rather bad because it&#x27;s just a tunnel though in very difficult conditions and large as you say is a bad comparison against a new railway network under a densely populated city.<p>Crossrail is large in the context it has new stations, depots, extensions, trains, and the very large amount of traffic it is expected to take under a very short construction period.<p>Looking at the entire picture doesn&#x27;t make the number seem ridiculously high. If it seems to high you need to look at where it&#x27;s all going its not just for a tunnel.