The Rapido Trains RS–18u features include:
- Accurately designed using a 3D scan of a real RS–18 and measurements from an active RS–18u
- Completely redesigned chassis and shell for easier access and disassembly
- Operating headlights, rear lights, factory–installed ditch lights and illuminated cab control stand
- Fully–operating tri–colour class lights (DCC required)
- Rapido's innovative dead straight metal side handrails with plastic stanchions, installed at the factory
- Unparalleled underframe detail incl. traction motor cables and other piping, re–railer and other parts
- Highly detailed cab interior with detailed control stand, operators seats and back wall panels
- All-new, improved drive system for 100% reliable running in DC and DCC
- DC/Silent (21–pin DCC Ready) or DC/DCC/Sound (ESU LokSound w/ accurate recordings from a real ALCo 251B prime mover under load) options


Canadian Pacific originally purchased their 72–strong fleet of RS–18s back in 1957 and 1958 over two batches, numbered 8729-8748 and 8749-8800. After over 20 years of reliable service, the CPR sought to extend the lives of their venerable 251B–powered locomotives, as a means to provide a reliable, efficient roadswitcher for branchline and regional services through the 1980s and 1990s. The RS–18 – already a fairly reliable first–generation model – was chosen to fulfill this important role

Starting in 1980, twenty two CPR RS–18s were extensively rebuilt in Angus Shops, Montreal to extend their useful lifespan another 10–15 years. Over the following 8 years CPR eventually rebuilt all 69 of its remaining RS–18s, being numbered 1800–1868. In the rebuilding, the units were substantially transformed in both appearance and performance.

They emerged with numerous changes, the most notable being the new chopped short hoods to improve visibility, the addition of full tri–colour class lights on both ends and new front number boards, and an improved uncoupling lever design. Under the hood, the newly–designated RS–18u featured overhauled engines and trucks, improved heating systems, new wiring, windows, cab insulation and control stands. The dynamic brake and 251B engine rated at 1,800 h.p. remained the same after the overhaul.

Of the rebuilt units, five of the RS–18u’s, 1800–1804, had U.S. duty paid on them, allowing them to run on U.S. branch lines with no restrictions. Other units were limited as to how long they may spend in the U.S. After purchasing the Delaware & Hudson, CPR assigned several additional RS–18u’s to the D&H for use in yard and local service, and were a staple on the Newport to St. Johnsbury wayfreight, among other services.

After CP, many units would go on and continue to earn their keep in shortline and regional service in both Canada and the US, proving that even after over 50 years of total service time, and a top–to–bottom rebuild courtesy of the men and women at CP’s Angus Shops, these MLW–built workhorses are able to continue earning their keep.