In 1962, the TdM shops drew up some plans to rebuild some of the PV&T’s RS-2s into C-420-alikes, and called them ‘rs-29’s (as in not quite a rs-32, but more than an rs-11), but these plans weren’t implemented because the central office wasn’t certain of a steam-shop-until-just-last-year’s ability to rebuild diesel-electric locomotives (it took until the BLWRS was kitbashed in 1967 for the shops to start getting the confidence of upper management back.)

In 2009, when the TdM was involved in an insanely complicated broker transaction to purchase a handful of used RS-11s, they discovered that two of those units had been in the process of being scrapped when the broker had removed them from the railroad that was selling them, and EPA emissions regulations would not allow remanufacturing with 251 blocks, so the old rs-29 plans were dusted off and updated with a Tier 3 powerpack (which became a Tier 4 powerpack before the carcasses were plucked from the storage yard and were rebuilt from the frame up.

These locomotives are 2400HP AC units with Cummins QSK50 prime movers (and a fairly sophisticated wheelslip control program to keep them from spinning out when starting a train or climbing a ramp in inclement weather.)

In 2023, the Parsons Vale started to slowly move towards avoiding the possible EPA banhammer that had been hitting other railways by sending some of the older 251’d locomotives to ILW to be remanufactured with an AC drivetrain and Tier 4 (the QSK50) prime movers. The two Eastport Dock & Terminal RSD-18s were the first to remanufactured, followed by most of the NSJL pool DL16cs (which also had their noses chopped at the time.)