PENNSYRR.COM by Jerry Britton


The class X23 box car was adopted by the Pennsylvania Railroad as a standard boxcar in 1912. It was their first 40-foot standard box car (nominal length), and was also their first built with a steel underframe, steel body framing and wood sheathing. Technically it was known as a composite single-sheathed house car. It was also the first PRR box car to be built using a combined alpha-numeric designation as all previous PRR box car classes had been identified using only alphabetical characters (XA through XL).

The class X23, as built, had a light weight of about 48,000-pounds, a nominal capacity of 100,000 pounds and a cubic capacity of 2,682-cubic feet. The first car (PRR 40001) was built by the railroad’s Altoona Car Shops and was placed in service during November 1912. Between November 1912, and December 1915, when the last car was completed, 6,911 class X23 box cars had been built by five different organizations. The railroad had built 1,011 cars at its Altoona Car Shops, the Pressed Steel Car Company had built 3,000 cars at its McKees Rocks plant, the Western Steel Car & Foundry Company had built 1,700 at its Hegewisch plant, the American Car & Foundry Company had built 600 at its Berwick plant and the Standard Steel Car Company had built 600 cars at its Butler plant.

The basic configuration of the X23 boxcar was also the basis for the class R7 refrigerator car, of which the PRR had 3,304, the class class K7 stockcar of which the PRR had 25, and the class class X24 automobile car, of which the PRR had 2,000.

Over the years various improvements were made including replacing the original roof with a lap-seam roof, 2D-F8 cast trucks replacing the original arch-bar trucks, KD-Brakes being upgraded with AB-brakes, and the 3-panel Creco door being replaced with a Youngstown corrugated door.

In 1943, during World War II, the PRR was experiencing a shortage of cabin cars (cabin car is a PRR term for caboose ) so 75 class X-23 box cars were converted to cabin cars and designated as class NX23.

As the class X23’s began to fall out of favor for revenue uses because of age, having been replaced by more modern all steel cars with greater load carrying capacities, they began being removed from revenue service. Many of these now out of service cars were transferred to work equipment service (X23 Series Camp Car Information for Modelers). When the shortage of cabin cars was relieved, also by the delivery of newer cars, many class NX23 cabins were also reassigned to work equipment service over a period of time. Interestingly, two class NX23 cabins actually remained on the freight car roster into the Penn Central era.

Most of the class X23 box cars converted to work equipment service were designated as "Tool and Supply", "Tool and Material" or "Supply" cars. The conversion from revenue to work equipment service included the installation of end doors and four rectangular windows on each side of the car. This was the most typical configuration. However, the class NX23 cabins that were converted to work equipment retained the porthole style windows. These tool, material and supply cars were a general-purpose car designed to be used for a variety of maintenance related tasks. Many of these cars lasted well into the 1960s and 1970s in their work equipment status.

Cars on the PRR roster (as listed in the Official Railway Equipment Register (ORER)):

Class Car Number AAR Class PRR Oct 44 PRR Oct 48 PRR Apr 52 PRR Oct 53 PRR Oct 58 PRR Oct 63 PRR Apr 68
X23 39995 44000 XM 3279 1076 21 10 - - -
X23 501580 501978 XM 312 101 1 1 - - -
X23 510652 511350 XM 610 166 3 1 - - -
X23 517367 517765 XM 292 104 1 1 - - -
X23 530021 530069 XM 40 14 - - - - -
X23 531039 531187 XM 130 43 1 1 - - -
X23 532827 532995 XM 143 46 - - - - -
X23 538003 538350 XM 284 73 1 - - - -
X23 556501 556550 XM 40 12 2 - - - -
X23 562094 562723 XM 543 193 4 1 - - -
X23a 340000 340036 GBC 37 37 4 1 - - -
X23b 103501 104259 XM 753 257 4 1 - - -
Roster data compiled by Rich Orr.


Types of Trucks Used

Class Car Numbers Truck Class Truck Name Qty cars:
X23     2D-F1 Arch Bar  
X23     2D-F2 Crown  
X23     2D-F4    
X23     2D-F4a    
X23     2D-F8 P.R.R.  
X23a     2D-F8 P.R.R.  
X23b     2D-F8 P.R.R.  
Truck data is from PRR documents circa 1940's. Other truck classes may also have been used.


Overview of Sub-Classes

  X23 X23A coke car X23B round roof
Capacity (lbs) 100,000 100,000 100,000
Weight (lbs) 40,000   46,900
Cubic Capy (cu ft) 2862 2862 3067
Distance between truck centers 32'6" 32'6" 32'6"
Length over strikers 42'6" 42'6" 42'6"
Outside width over side sill 9'0.5" 9'0.5" 9'0.5"
Inside width 8'10" 8'10" 8'9.5"
Door width 6' 6' 6'


177 X23 Second Image 177 X23 Top Image 1


The X23 has been produced in HO scale by Overland (brass), Rail Classics (brass), Rapido, and Westerfield (resin kit). The X23B has been produced in HO scale by Funaro & Camerlengo. Mount Vernon Shops offers decals for MoW service.

7001LargeRapido X23 (test shots)