Class 4 (Locobase 11558) 
Data from Baldwin Locomotive Works Specification for Engines as digitized by the DeGolyer Library of Southern Methodist University Vol 20, p. 76, Vol 26, p. 22, and Vol 62, p. 109. See also the Hobo's Guide to the Pennsy's detailed description by Bill McBride of the P&H at http://kc.pennsyrr.com/guide/pemberton.php . Works numbers were 14606 in January 1896, 23054 in October 1903, 32597 in January 1908, 52294 in September 1919.
The 24.4-mile (39.2 km) Pemberton & Hightstown Railroad, also known by its owner's name as Union Transportation, connected two anchors in New Jersey's farm belt east of Trenton. It was a key route for farmer to receive goods, ship their products, and travel for their own business or pleasure.
The Hobo's Guide explains why this service remained unchanged for so long:"No single or combination of products appeared to dominate, thus allowing the UT to rely on a tradition of mixed train service for some 43 years. Typical freight included milk, cranberries, hay, and straw. Freight extras ran to accommodate excess loading of gravel, and later potato and tomato crops for Campbell's Soup Company in Camden, New Jersey."
Long overseen by the Pennsylvania, although controlled by UT, the P&H was nominally merged in 1915 with the Philadelphia & Long Branch and the Kinkora & New Lisbon as the Pennsylvania & Atlantic. The locomotives were lettered as Union Transportation. Taken together, the P&A measured 83.4 miles (134.3 km).
A key stop was Wrightstown, which was the closest to Fort Dix.
These little Eight-wheelers were built to a common design that differed little for 23 years. The 1919 order reflected the P&A merger in its specification of "PRR Standard" components such as cylinder and gauge cocks and the stack top. It also weighed a little more--65,000 lb (29,484 kg) on the drivers, 96,000 lb (43,545 kg) overall.
Some of the quartet hauled the passenger locals until the early 30s, when the passenger business was shut down. Some remained in service into World War Two. The 5 was sold to the Peoria & Pekin Union in 1915 as their Class B, road #16. It was retired in 1928.