The bridge over route 1 is still there, but no track on it.
Just to the west of it is the start of the bike trail going north along the
Bel Del ROW to Lambertville and farther. DOn't know if you can walk on the bridge.
On the east side of the bridge is the old PRR MIllham branch, which is still active (from the originalTrenton -NB line as mentioned by SPUI).
The old Bel Del connection to the PRR mainline (the wye SPUI mentioned)
which was just northEAST of the trenton station near Lincoln Ave, is gone. I think it went out in the early Conrail days, but not sure.
If you look at maps.google.com in "map" mode it shows as still
there, but in from the "satellite" picture mode you see it is gone.
You can also see a bridge still there crossing the canal from the west end of the Route 1 bridge. THis was from the PRR "Enterprise branch"
(now long gone) which left the Bel Del there to cross the canal to go up past what is
now Helene Fuld hosptial to the industrial area north of there, along the northwest side of the feeder canal (the canal to New Brunswick).
NOrth of Helene Fuld the ROW ran on the old canal towpath on the northwestside of the canal -- the Millham branch was opposite on the east/south side
(The canal is actually under route 1 for about a mile in this area,
if you don't see it in photos).
The wye a few miles up the main line where the Millham branch comes
into the mainline near WHitehead Rd. is still there. Conrail uses this branch to access the
north end of what now NJT calls the River line sometimes (usually
it comes up from Camden). From Morrisville Yard, they go through trenton station, then onto the Millham branch at the wye, the loop back south past the BelDel bridge over route 1, then back over the mainline
and onto the River line along Canal St. The direct connection to the main line shown between this branch and the mainline (in the east quadrant
of the crossing) still shown on the google "map mode" is gone.
My favorite piece of trivia is that this loop is the only connection in NJ
between "North Jersey rails" (trenton and north) and south jersey rails
(e.g. the Riverline, and everything from Camden south). (until they
restore the CNJ SOuthern division, from Lakehurst down to Winslow, that is!)
JS