Non diagonal stacker creates path with wrong train length for some values.
Example:
1) 1-1 train. Expected stacker length = 2. Resulted = 3.
2) 1-4 train. Expected stacker length = 5. Resulted = 4.
3) 2-4 train. Expected stacker length = 6. Resulted = 5.
4) 5-2 train. Expected stacker length = 7. Resulted = 6.

Diagonal variant seems to work fine (or at least much better).

Also stacker menu does not ask for Double-Headed train variant and creates something close to Single-Headed train

Hi!

Thank you again for the detailed report. I think I have found and fixed the incorrect length calculation for non-diagonal stackers.

I have also added an option for single-headed or double-headed train sizing when creating a stacker.

You can download the experimental Railwright 0.3.11 test build here:

Download Railwright 0.3.11 test build

I am currently away from home for work, so I cannot test the build inside Factorio myself yet. All automated tests and packaging checks have passed, but confirmation from an actual game would be very helpful.

This is an unreleased development build, so please make a backup of your save before testing it.

After downloading, extract the GitHub artifact once. Place the enclosed railwright_0.3.11.zip in your Factorio mods folder without extracting that inner ZIP.

If possible, please test:

• 1 locomotive + 1 wagon
• 1 locomotive + 4 wagons
• 2 locomotives + 4 wagons
• 5 locomotives + 2 wagons
• A double-headed train, such as 1-4-1
• Both non-diagonal orientations
• The diagonal variant, to make sure it still works correctly

If a lane is still too long or too short, please send a screenshot showing the complete stacker and the selected settings.

Thanks again for helping test it!

Sure, no problem. Here's what i found so far, but note, that I also don't have time thoroughly check each and every option.
General:
double head option is named and placed in the wrong place and part compared to other station types.
Bottom summarized info is differentiate from other station types particulary in this option. Consistency and readability in that part is expected, but for now it lacks both, so it's feels more like debug and error output.

Non-diagonal
1-1 train can not fit. 1-1-1 works fine.
other lengthes are ok.
Signals can be placed further to the curved lines, which can save space, unless stacker is planned to be reconfigured to the station, which is never, i think. (older issiue)

Diagonal
Diagonal "Left-right" and "right-left" variants just rotates the blueprint, instaed of creating mirrored one like stright variand does (older issue).
Length feels to work fine