Broadway Limited delivers the Pennsylvania Railroad M1a and M1b 4-8-2 Mountain type steam locomotives in N scale with premium detail and authentic performance. Used primarily for hauling freight, many PRR crews regarded the M1s as the pinnacle of the railroad's steam power. Standout features on both classes include the square-shouldered Belpaire firebox, 72-inch driving wheels, and a large cross-mounted air tank at the front of the locomotive. The differences between the M1a and M1b classes are minor: the M1b models have firebox circulators absent from the M1a, with the sole visible distinction being extra cleaning plugs on the firebox sides for maintaining the circulators.

This 2024 production run offers three prototypical road numbers of each class, an unlettered M1a, an unlettered M1b, and two PRR-style fantasy paint schemes. Stealth Series models are No-Sound, DCC-Ready, and operate on DC out of the box with directional front and rear lights. Other lights are always on with track power. An 8-ohm speaker is pre-installed for easy DCC/Sound decoder installation.

- Stealth Series: DCC-Ready Out of the Box with No Sound
- Directional Front and Rear Lights Out of the Box
- 8-Ohm Speaker Pre-Installed for Easy DCC/Sound Decoder Installation
- Precision Drive Mechanism for Heavy Towing and Smooth Slow Speed Operation
- Die Cast Body with Die Cast Chassis for Maximum Tractive Effort
- Premium Caliber Painting
- Prototypically Accurate Paint Schemes and Road Numbers
- Many Separately Applied Details Including Handrails, Grab Irons, Ladders, Piping, Whistle, and Bell
- MicroTrains-Compatible Couplers (2)
- Compatible with Code 55, Code 70, and Code 80 Rail
- Minimum Operating Radius: 9.75 Inches
- N Scale 1:160 Proportion
- 4-8-2 Mountain Type Wheel Arrangement
- Square-Shouldered Belpaire Firebox
- 72-Inch Driving Wheels
- Cross-Mounted Air Tank at Front of Locomotive
- Paragon4 Sound Series Also Available
- Compatible with BLI CV Setter Accessory