You can but the track has to be built for it. Japan has stations that are passed at 320km/h (200mph). You need minimum four tracks (two platforms, two passing) and curves/gradients suitable for the speed, along with noise mitigations as necessary.

If you're trying to re-use tracks and stations built in the 1800s that's possibly less feasible.

In an ideal world you'd have bypasses or tunnels to help them keep up speed, but that all depends on land allocation and investment. If you're stuck with old windy narrow tracks then yes youre going to be limited.

Trains like shinkansen can go very fast through dense urban areas, i think mostly in tunnels - but also because they spend a lot to straighten the routes. Obviously there are still some slow sections, but they minimize it by design - and probably a willingness to bulldoze historical land ownership.

I guess in Philly the route probably winds around a bit. https://www.openrailwaymap.org/ It looks like all lines funnel through a couple of very tight curves around the centre. That looks like quite a sensitive choke point.

But apart from that section it looks like the acela limit is over 100mph for quite a lot of the urban area around Philly, which isn't too bad. Its not like its crawling around at 60mph for half the distance.

There's another interesting looking slow chicane in Wilmington. In that case there's what looks like an ideal bypass line already there for any express. It runs through a massive siding (freight maybe?) that is limited to 10-30mph. Looks like a no brainer to me, strengthen those bridges and run any express through that. plenty of dead space around there to reconfigure just one level crossing i think to worry about. most of it is 3-4 tracks already judging by google map.

I heard that US freight and passenger rail don't like to share and enjoy though so probably that's a non starter.

The speed with high speed rail is usually made between cities, less so in dense areas. But that doesnt mean there is no gains to be made by improving track and running at say 130-160 km/h (80-100 mph)

To my knowledge these trains can alao accelerate quite fast because they are electric trains.

Its literally the same trainset by the same manufacturer as the TGV, hence the comparison. The highest track speed on the northeast corridor is 160 MPH, which is why they're calling it a 160 MPH train.

The problem is the infrastructure not the train. Its a good train.

You're not understanding the difference between the line speed and the train's design speed. The train is capable of comparable speeds, significantly higher than the track speed