There are four tracks, but they are shared by local commuter services, rapid commuter services, intercity regional services, and the actual high speed trains.

To put this in context, by the time suburban development started in earnest in the US, the private railroads were in free-fall after the war. It took until the '70s for Amtrak to put the (passenger) divisions of said railroads out of their misery, and Nixon did not anticipate Amtrak surviving the decade; Amtrak was supposed to decline out of existence. It never quite did that, but it also never quite got back on its feet, and so now the passenger rails are quite lacking.