I checked the two as-yet unused NP decal sets which I have, but both are for older cars, with a totally different font from what you need. I did find sans serif numerals in white and probably sized reasonably for BLT and New dates, but there's no matching BLT or NEW lettering. The font is probably different enough from the NP style which you have, that the difference, because the two styles would be side-by-side, would be noticeable. Likewise, I have 3s and 7s probably sized properly for dimensional data, but stuck-in with what you have they would likely stand out, too. All of these are from an N scale set for CNR side-dump gondolas (I model in HO, of course, but the spelled-out CANADIAN NATIONAL in the set was a suitable size, in HO, to go on '30s-built general service gondolas).
I most likely have sans serif BLT and New lettering, plus numerals to create the dates that you need, but they're all Champ decals, with a decidedly different density of ink - another thing that would make them perhaps too noticeable.Modelling the '30s, I have noticed a dearth of "3"s in many decal sets, and have, on occasion, resorted to modifying "8"s, although that doesn't work well for all fonts.
Wayne
The original figures (CAPY 153000, LD LMT 153500, LT WT 65200, NEW 11-67, BLT 11-67, CU FT 1977) came from a combition of information from the NPRHA web site (car diagram) and from rrpicturesarchives.com (information from pictures). However, based on the following information (CAPY 153,000 [from NP] Max Gross Weight 220000 [rrpa], Load Limit 155000 [rrpa]), I have come up with some slightly different numbers: CAPY 153000, LD LMT 155000, LT WT 65000.
I have pieced decals for weights before. (I have 10 Thrall coal cars as an example of this point.) The main issue I am running into is that the 1399 set doesn't have all of the numbers/letters that would be needed. (As an example, there are no 7s for the built/new date and the CU FT #; there aren't enough 3's nor are there any Bs which are needed for the Car Type decal which is GB. BN decals have a generic boxcar weight set that I used for the Thrall cars but the font is different than the print on the NP set. (I pulled one of the sheets I have out and checked.) That I am aware of, there is no sheet that has a generic font for NP.
I looked up both of the decal sets which you mention, but it's next to impossible to read them, especially the smaller lettering for the dimensional data, on my monitor.However, the 87-1399 set gives you the CAPY/LD LMT/LT WT parts of the needed lettering, and I'd guess that the NEW/BLT/CU FT stuff is on those sheets, too. All that's left is to search the sheets for the numerals required to put together the particular weights and dates that you want. I do this sort of stuff all the time, although the car shown below is a fairly extreme example of the process...
The lettering is comprised of 168 individual pieces of decal.
As I model the late '30s, I'm not familiar with the determination of weights and capacities for cars over 100 tons, but there's a discussion regarding that HERE. The seventh post in that link is probably the most concise explanation about determining the actual weight values used.
For any era, the sum of the load limit and light weight must be the same for all cars of a given nominal capacity (CAPY). For my era, the arbitrary sum for 40 ton cars was 136000, 169000 for 50 or 55 ton cars, and 210000 for 70 ton cars. Each car is weighed empty, when new (that weight is to what's referred when you see "NEW" on a freight car), and is weighed periodically throughout its service life (and the "NEW" replaced with the letter code for the station doing the weighing, plus the date it was done). If you subtract the car's weight (LT WT) from the appropriate number for its particular nominal capacity, the resultant number is the car's load limit (LD LMT).
OK, friends, I am in need of help yet again. Back to the NP GB 56050-74 car that I am trying to model. I have the Microscale 87-1399 set which gives me the billboard lettering, the road name and number, and the numbers for the car ends. I haven't been able to find the rest. If I have judged it correctly, I need something in the line of CAPY 153000, LD LMT 153500, LT WT 65200 and NEW 11-67.Also needed the decals for BLT 11-67 and CU FT 1977, if possible. I tried getting an 87-777 set which completely wasn't right. I couldn't find any of the other Microscale sets that seem to have the right pieces. (If it helps I model post-merger to 1980.) If anyone has any idea of any other company's sets that have the required info, I am all ears. As usual any assistance that can be provided would be most welcomed.