Sorry I only 21” cars. If MTH states they will handle 042 then I’d go for it if it’s something you want. They are a unique looking engine. Being a NH fan they were a must have. If your curves are only at the end of your run and your only negotiating those 2. Shouldn’t be an issue looks wise. Big Boys are rated for 072. Lots of overhang with the long boiler. Doesn’t stop anyone from buying them.
Will the 18” cars negotiate your 042 ? Do you have a wheelbase measurement on the 70ft. car. The 2 outermost axles. The blind wheels are the inner wheels on the DL109. I can get you a measurement if you think it will help. I would think the overhang would be pretty close between the 2.
