It was designed for passenger trains, particularly on commuter lines, and became a fixture on suburban railroads (notably the Long Island Rail Road) until the mid-1950s.

Smaller drive wheels than an Atlantic and the lack of a trailing truck put more weight on the drivers and produced an engine with great power and acceleration but a lower top speed.

The 4-6-0 wheel arrangement could provide sufficient tractive effort, (41,000 lbf (180 kN) of force) while at the same time allowing the locomotive to accelerate the train more quickly.

In his book Pennsy Power, Alvin Staufer cites a G5-led milk train that ran 145 miles daily through rural Pennsylvania, trailing an old combine for the occasional passenger - which sometimes included a hunter that the crew would let off at a clearing in the woods.

Fan trips as early as the 1930s also were headed by ten-wheelers: "'Off the Beaten Track' excursions covering branch lines frequently drew G5s power, since larger engines were prohibited."

Work trains were another assignment too menial for mainline power but fine for the versatile G5s, which often elicited adjectives such as "gutsy," "squat," "tough," or "husky."

[1] The G5 was the primary passenger locomotive on the Long Island Railroad until the end of steam operations, sharing the duty with K4s's and other G5s leased from the PRR, as well as diesels such as the Alco RS3 that ultimately replaced them.

The museum initially worked to secure funding for the full restoration of the locomotive to operating condition, including a conversion to oil firing, and a new tender.

[6] #35 was inspected by contractors from Steam Operations Corps, and thoroughly cleaned in preparation for the locomotive being shipped to Alabama for further restoration, but those plans fell through.