The first sighting of the train on the Old Main Line (OML) comes from I-95 over the Patapsco River.

One arch of B&O's venerable Thomas Viaduct is visible on the right marking where CSX's Capital Subdivision splits off.

Trains curving off the OML often pause at St. Denis awaiting signal to proceed into Baltimore. That's Rolling Road above CSX engine 3254.

The two brackets attached to the bridge previously held signals to control the two tracks of the OML. Yes, into the 1950s the OML was double tracked. The brackets have been devoid of signals since around that time.

Our train was waiting for these much newer signals to change from all red (stop) to red-orange-flashing green, which translates to Medium Approach Medium: "Medium speed through turnouts, crossovers, sidings, and over power operated switches; then proceed, approaching next signal not exceeding Medium speed."

Link: CSX Signals Chart (PDF)

The engines roared to power soon after getting the green light, headlights and horns blaring. CSX 3254 is a General Electric model ET44AC.

When chasing a train, railfans often refer to its "train symbol." CSX employs train symbols consisting of a letter and number, for example, "Q116". Since I do not know the symbol of this train, I'll refer to it by the number of its lead locomotive.

Link: CSX Train Symbol List

Assisting is engine 5323 sporting an unusually yellow-tinted CSX monogram.

A mild winter day brings the regulars out to watch the action at St. Denis.

Beyond I-195 our train switches from the Old Main Line track (left) to the Cap Sub's track Number 2 Main (right).

Sulphur Spring Road may end here but the railroad does not. There's no sign of CSX 3254... or is there?

Hey, there's our train!

Wait a sec, that's CSX 3241, not our beloved 3254, which has been given priority to proceed ahead of these two through Baltimore's Howard Street Tunnel bottleneck.

Here at the undefended border between Baltimore County and City, we've arrived prior to 3254 where signals guard the entrance to Mount Clare Yard. Our train is being shown an orange-red-red signal to Approach: "Proceed prepared to stop at the next signal. Trains exceeding Medium speed must immediately begin reduction to Medium speed as soon as the engine passes the Approach signal."

Sure enough before long CSX 3254 rumbles to what's left of the Gable Avenue grade crossing at the southwest corner of Mount Clare Yard. Here the current main line (foreground tracks) splits from the Old Main Line (far right).

At distant left something looks odd about the consist...

Aha, we're not the only ones chasing 3254! A train of autoracks is keeping pace alongside on track number 1. Soon both trains will ground to a halt within seconds of each other.

From Zepps we can get an overhead view of the yard and its idle trains.

Three locomotives vie to be the first to cross Hollins Ferry Road. Who's it gonna be?

Was there any doubt? With downtown Baltimore looming beyond I-95, our train is first to get the orange-green-red Approach Medium signal: "Proceed, approaching next signal not exceeding Medium speed."

Then, without movement of trains, either the engineer or dispatcher activated the Hollins Ferry Road crossing lights...

... and CSX 3254 powered up...

... leaving the other trains, and us, behind -- some 2 hours since departing St. Denis. The Howard Street Tunnel is about 2 miles ahead.

Back at the Patapsco River crossing, the Old Main Line rests briefly before the next chase candidate.