148 or 125?

Depends on the timeframe. I model the 1920s so I'm using code 125 for the main and code 100 for the spurs. I may switch to code 83 for the spurs and save the 100 for the yard.

You are coming from 3-rail?  Stick with .148 track and .172 wheels.

I have been in 2-rail for 70 years, machine my own drivers and main frames, and I have lousy luck with fine scale wheels and track.

However, if you are truly a careful modeler and an accomplished machinist, you can go with finer scale track and wheels, all the way to Proto-48 and still be successful.  If you are an average modeler, stick with the tried and true components to avoid frustration.

I like 125 for main lines, 100 for yards.

Take this with the proverbial grain of salt since I'm coming from the 3-rail side of the house, but if I were starting over and in 2-rail AND hand-laying track, I'd probably go with Code 125 on the mainlines and Code 100 for the spur tracks and yard. Height wise, you'd be looking at 6" rail height for the Code 125 and about 5" for the Code 100.

I have some older O scale 2 rail  from the 40's and some have a deep flange , I chose 148 for the main line and 125 for side tracks.   The 148 will handle most all wheels including the major brands of toy trains, weathered on scale ties it looks fine, with out having to turn down flanges. electrical is not an issue, as I am converting to dead rail

The Pennsy mainline rail weight ranged between 132 and 152 lb.  I picked code 148, which corresponds to a height of 7.10".  That is close enough to the 7  5/16 " height of 140 lb rail

Ralph,

Model rail code refers to the height of the rail. If you measure the rail, Code 100 is .100 inch high, Code 125 is .125 of an inch...

Prototype rail can be different from different manufacturers. I've linked to a document from the ATSF which list various manufacturers of rail and the sizes based on the weight of the rail. There are cases in here that different weights of rail had the same heights.

http://www.shamokindivision.co...nsions-of-rail-1.pdf

The PRR Mainlines were heavy rail as mentioned above.    So Code 148 would represent that well.    I would use code 125 for sidings.    I'd be tempted to try code 100 on industrial track, but not sure.    I do have some older steamers and the flanges may be just big enough to hit the heads of some spikes if not totally tight down.    I have had no issues at all with code 125.   My yard and ladder tracks are all code 125.

@prrjim posted:

The PRR Mainlines were heavy rail as mentioned above.    So Code 148 would represent that well.    I would use code 125 for sidings.    I'd be tempted to try code 100 on industrial track, but not sure.    I do have some older steamers and the flanges may be just big enough to hit the heads of some spikes if not totally tight down.    I have had no issues at all with code 125.   My yard and ladder tracks are all code 125.

So, how do you transition from 148 to 125 or any other step-down situation?

Shims...?

Mark in Oregon

@adferraro posted:

Depends on the timeframe. I model the 1920s so I'm using code 125 for the main and code 100 for the spurs. I may switch to code 83 for the spurs and save the 100 for the yard.

Wow...code 83. That's getting pretty small. I think that's more or less the "standard" now for HO. Would like to see some pictures, if and when you do that. 👍

Mark in Oregon

@bob2 posted:

You are coming from 3-rail?  Stick with .148 track and .172 wheels.

I have been in 2-rail for 70 years, machine my own drivers and main frames, and I have lousy luck with fine scale wheels and track.

However, if you are truly a careful modeler and an accomplished machinist, you can go with finer scale track and wheels, all the way to Proto-48 and still be successful.  If you are an average modeler, stick with the tried and true components to avoid frustration.

This is an important point for me. I want to be sure that I'm not restricted to run locos and cars to the point where it becomes difficult to find stuff to run on my layout. It seems that .148 provides the best opportunity.

Yes, I'm coming from 3-rail (and HO).

@Strummer posted:

Wow...code 83. That's getting pretty small. I think that's more or less the "standard" now for HO. Would like to see some pictures, if and when you do that. 👍

Mark in Oregon

Yeah, even code 100 is used in HO.

Something to consider is that the wheel treads are a bit wider and the flanges a bit larger on the models. Those proportions will make the smaller rails look even smaller. Most are not using 115 treads and truly scale flanges. Once the track is ballasted and the rails are painted and weathered, the rails really don't jump out at you like they do when they are not painted.

The Pennsylvania modelers I know who are building layouts are using code 148 for their heavy mainline traffic.

Another consideration is our 5 foot gauge track.  Most cannot see it, but I perceive our track as being too wide for our models.  Smaller rail exacerbates that illusion.

O Scale rail code equivalencies to HO rail:

148 in O is equal to code 83 in HO or 132-140 pound rail (probably the most common modern mainline rail)

125 in O is equal to Code 70 in HO or about 100-110 pound rail (most common on secondary trackage or sidings)

100 in O is equal to code 55 in HO or about 75-80 pound rail (suitable for little used spurs or early 20th century secondary trackage)

83 in O is equal to code 46 in HO or about 60 pound rail

Here's a picture of my first module. The main is code 125 as mentioned and the spur is code 100. All handlaid.

Wheel profiles are .145 and nothing hits the spike heads. It tracks well too so far.

I'm not sure yet about the code 83, but I think it's worth testing out.

@Jim Scorse posted:

O Scale rail code equivalencies to HO rail:

148 in O is equal to code 83 in HO or 132-140 pound rail (probably the most common modern mainline rail)

125 in O is equal to Code 70 in HO or about 100-110 pound rail (most common on secondary trackage or sidings)

100 in O is equal to code 55 in HO or about 75-80 pound rail (suitable for little used spurs or early 20th century secondary trackage)

83 in O is equal to code 46 in HO or about 60 pound rail

Thanks, Jim. This is a great guide.

@adferraro posted:

Here's a picture of my first module. The main is code 125 as mentioned and the spur is code 100. All handlaid.

Wheel profiles are .145 and nothing hits the spike heads. It tracks well too so far.

I'm not sure yet about the code 83, but I think it's worth testing out.

Very nicley done. Are you using nickel-silver rail?