Locomotives Dimensions - MLW RS-10, RS-18, RSC-14
In 2015 and 2017, I took ground-level measurements of CN RS-18 #3684 preserved at Exporail. In making the drawings, I made a few minor changes to the measurements (+/- 0.25") so all the totals add up.
- The hood height (8' 10") was taken from MLW M-636 measurements and confirmed from online sources; all other measurements were taken directly.
- Fuel tank plug locations varied slightly from front to back on #3684 (as well as from other units) so the measurements listed are symmetrical averages from #3684.
- Many dimensions are shared with the MLW RS-10 as well as the ALCO RS-11, RS-32 and RS-36.
- Most hood and handrail dimensions are the same on both sides, except for the middle three pairs of engine room doors (which are reversed).
Variations from the listed measurements:
- Units with Type B trucks have a 9' 4" truck wheelbase and a different handbrake chain, without the pipe and pulleys on the inside of the underframe.
- Early RS-18 units had cast coupler pockets with slightly different dimensions from the fabricated version (illustrated).
- Fuel tank and air reservoir measurements don't apply to units with transverse fuel tanks and air reservoirs (listed below in RSC-14 measurements).
I did not take measurements of ONT RS-10 #1400 at Exporail in 2015, and when I went back in 2017 it was no longer on public display. However, using a combination of details photos of #1400, diagrams, measurements of an MLW RS-2 (which shares much of the same door spacing) and prime mover dimensions - along with the many dimensions shared with the RS-18 - I was able to narrow down the hood dimensions of the RS-10 to a level of precision comparable to direct measurements.
The diagrams below list the dimensions that are different from the RS-18; the underframe is almost identical between the models. The RS-10 shown represents CN #3074-3093 (RS-10S) as-built and with Type B trucks, as opposed to the RS-18 drawings representing #3677-3700 as modified and equipped with lightweight trucks. Otherwise, the drawings of the two models are as similar as possible (a late RS-10 and an early RS-18 built to the same CN specifications).
In summer 2018 I measured CN RSC-14 #1754, preserved at the New Brunswick Railway Museum. Conveniently, not only does this unit differ from #3684 at Exporail by the swap to A1A trucks, it also (like all RSC-14's) is a later-production unit with transverse fuel tank/air reservoirs and L-channel handrail stanchions, thereby filling in many gaps in my RS-18 measurements.
- The general hood and underframe dimensions (including overall length and truck centers) are the same as other RS-18's. For the most part, I didn't measure dimensions that I had already obtained from #3684, but where there was overlap, measurements of #1754 matched exactly with those of #3684.
- The long-hood handrail stanchions have the same spacing as on earlier units with square stanchions bolted to L-brackets on the walkway, but they are all moved slightly toward the cab.
- Underframe and truck measurements suggested a walkway height 0.5" higher than in my existing RS-18 drawings up to that point. While I initially dismissed the discrepancy, I realized I had actually drawn the frame too low - so I ended up revising all the drawings with a 0.5" higher frame.