No

Code 40 is approximately 60# rail. For reference, most of the rail on the Transcontinental Railroad in 1869 was made with 56# rail, which was deemed "adequate" at the time. So no, it wouldn't support much more than an old-time 4-4-0.

From the DCC Wiki ...

Start of quote: “

In general, heavier tonnage, heavier rail. For N scale, divide the code number by 2, or for O, multiply by two to get an approximate size. For Example, the C83 equivalents for N are 45, and O, 148. So C40 and C150 are appropriate. The NMRA recommends C40 for all applications in N Scale. For more details see  NMRA Data Sheet D9r Rail Size. Choosing the appropriate rail size will make your models look much more like a model.

In the 19th century, rail weights of 40 to 80 lbs per yard (approximately 20 to 40 kg/m) were typical. In the 20th century, weights increased to the 112 to 145 lbs seen today. For most modellers, Code 83 is the best compromise for main line trackage. Lighter rails can be represented by C70 and C55 rail for sidings, yards or lightly used branch lines. C100 can be used to represent the 155 lb. rail used by the Pennsylvania Railroad in their mountain districts.”

End of Quote.

So, while it would likely work on Code 40 if the flanges are small enough, and the prototype might have switched cars on sidings this small, in practice I would say code 55 is likely the minimum equivalent to prototype that would have been in use by the time locomotives of this weight were introduced, which was around 1904 and after ( Mikado History)

I don't think that works...

The NMRA RP25 wheel profile says that the flange depth is 0.71mm. In old money, that's 0.028". Code 40 of course is nominally 0.040", so superficially you'd think that could work. But 0.040" rail height is from the top of the tie to the top of the rail, and in particular it does not include the "spike head." If the code 40 rail is fastened to the ties using, say, solder or contact cement, yes this may work. But if you put spikes in, I'm pretty sure that some of the spikes will hit the flanges and likely cause derailments.

Having said all that, a quick google turns up the fact that ARA defines the 90 lb rail profile as 5 5/8" height, which is 0.064" or approximately "Code 64." Apparently ASCE's definition for 60lb rail is 110mm in height, or 4.33" in real life. My calculator says that such rail would then be 0.049" or "Code 49" if taken literally. Therefore I'd say that code 40 would likely be the rough equivalent of about 40 lb rail, if such a thing existed. (I don't think it has in the 20th or 21st centuries, perhaps outside of narrow gauge or maybe temporary logging railroads.)

Juxen, Good to know, the rail

Juxen,

Good to know, the rail on this siding is code 55, and my Mikado doesn't often visit this branch line terminus. Usually  a 2-8-0 does, and in the summer a 4-6-0 on excursions.

Candofan, All my brass locos

Candofan,

All my brass locos ran on code 40 rail on a friends layout, but his older brass locos makd in the 70s hit the spikes on his sidings.

Mike,  My branch line

Mike, 

My branch line terminus is code 70, and the sidings code 55. 

If the wheels are pre-RP25

If the wheels are pre-RP25, they would have much deeper flanges than current wheels. I know that RP25 dates from the early 1960s, as I have a book with a publication date of 1963 that talks rather excitedly about them. My impression is that most Japanese brass builders adopted RP25 almost immediately. I have never seen a Japanese brass model with the earlier "pizza cutter" wheels. Most of mine date from the mid-70s or later, although the handful that I do have from the mid-to-late 1960s do have RP25 wheels. (These are from Hallmark, Red Ball and United), And there were lots of builders, so it's entirely possible that some had deeper flanges.

I'd say that code 40 is unrealistically small rail for what was designed as a mainline loco. I don't know what CN used in the 1910s or 1920s but I'm pretty sure it would have to be 90lb or heavier.

One thing is for sure: if you run HO on code 40, you will have little margin for error. Maybe that's fine (you did say that this loco only visits this location rarely), but you should be doing it knowing this. In my experience, operational failures (derailments, split trains, etc) usually happen when TWO things are out of spec, not just one. In this case you're more or less putting the flange depth clearances out of spec to begin with, so anything else that's amiss is likely to cause trouble.

Rail

Since we had 56-70 rail in old industrial and yard tracks in 1980, I would say that yes, a Mikado could be on that size rail in 1950.

Major caveat:  It wouldn't be main tracks, passing sidings or major yard tracks.

It could be industry spurs or secondary yard tracks on old, low traffic branch lines.  Pretty much if the rail broke on one of those tracks, it would be replaced with heavier rail, or rail would be removed from another out of service track to replace it.  In 1980 we were having to scavenge rail from out of service 90 lb tracks to keep older 90 lb yard tracks in service.

In HO if you solder the rails to PC board ties and have all NMRA flanges, you can operate on code 40,  Spike heads or oversize flanges will cause interference.

A friend of my had a couple code 40 on PC tie spurs on a former layout but had all sorts of problems with the rail kinking due to changes in temperature and humidity ( in both the rail and the roadbed).  Can't remember what the PC tie spacing was, but I suspect it wasn't close enough.  Also he had issues with the rail pulling off the PC cladding or breaking loose from the ties, which is probably more of a soldering technique issue.

Dave, I knew a model

Dave,

I knew a model railroader that modelled the forties and said CNR Mikados could go on 60 to 70lb rail. His mainline was code 70, and his branch line was code 55. He had to taper down the flanges on his older brass locos that were made in the early 70s so they could spot cars on the code 40 rail rural sidings.

Someday I'd like to make a little diorama of an old siding with code 40 for the fun of it and use it to display and old loco.

Candofan,I think VanHobbies

Candofan,

I think VanHobbies older brass models had deeper flanges. The only VanHobbies models I have are two 0-8-0s, but never tried running them on code 40, but do work fine on code 55. 

GE 44 tonner on Code 40 rail

This rail is 3 5/8 " tall , ( marked  A&RI&S, Troy Steel ,1876) which would be close to code 40 in HO scale. The engine doesn't seem to have any flange clearance issues....DaveB

DaveB, You must put this shot

DaveB,

You must put this shot in the next "Weekly Photo Fun" thread.

BTW, Iove those 44 GE tonners and always wanted to make a CNR one like this

or this

In this B&W shot, what size rail do you think it is?

what size rail ?

Hi Dee, Maybe 5 inches or so tall? So code 55 in HO scale?   If you could find something on the engine that you know the size of and in the same plane as the rail you might be able to scale a better guess.....DaveB

DaveB, Good idea. 

DaveB,

Good idea. 

4.5" tall rail on the Washington & Old Dominion

When I was a child the W&OD went belly-up. After riding my bicycle to the Vienna VA yard, I found a very short piece of rail that I turned into a bookend. It is 4.5" tall. So that would be ~Code 65 in HO.

The W&OD in later days mainly ran GE 70 ton engines. The largest diesel I saw was months before the RR shut down, a leased C&O Alco S1-2-3-4. I don't know which it was, no photo in my possession, and that was the first Alco I ever saw.

I haven't read any historical documents suggesting medium sized steam locomotives ever ran on that short line.

Regards, 

Bob

4.5 inches tall rail

4.5 /87=.0517 or close to code 50 for HO scale ( if anyone makes code 50? )  I'd probably just go with code 55 ....DaveB

Dave, that shot is amazing ...

Maybe it's an optical illusion, the model track you have #36 posed upon, looks much larger than Code 40 ... ?

Wrong rail

Mike, I had the same thought when I first looked at Dave’s photo (really cool photo by the way Dave).  But then I realized I wasn’t seeing the rail for the track, to twist an old saying a bit.  The big chunk of rail the track is sitting on would scale down to about code 40 in HO.

Dave, that rail would make a heck of a bridge across a doorway for your layout.  Not a removable one though.

Code 40 rail, etc ...

The Sugar Pine Lumber Company laid its entire line with 60-pound rail and that worked just fine with the Alco 2-8-2T (about 95 tons) and Alco 2-8-2 (about 130 tons including the tender) locomotives that frequented the line, but when the company purchased the 2-10-2T Minarets type (and the only true Minarets type loco) at 133 tons, with all the weight on the loco and no tender, it started breaking the rails. The company then relaid the portions of the line, the "logging mainline" so to speak, on which that loco would typically operate. But the smaller rail remained in use on all spurs and such, with the 2-8-2T locos in use, with great success.

Jeff Johnston

Jeff J Very interesting. I

Jeff J

Very interesting.

I knew a model railroader that swore CNRs 2-8-2s and 4-6-2s could run on 60 lb rail, and the 2-8-0s spotting cars on 40 pound rail sidings. 

the old rail

in my photo was from the Visalia electric line. My grandfather got it when parts of the line were torn up back in the 1950's I guess. It was supposedly originally laid on the SP donner route, than as the Donner  line got upgraded the old rail was moved down to use on the then new Visalia electric. My grandpa kept it in his barn and used it as a crude farmers anvil....DaveB

The old rail

That’s a neat piece of both railroad and personal history.

DaveB,Thanks for sharing

DaveB,

Thanks for sharing that.