I'm Sven, playing Factorio since 0.14 and new into modding Factorio. Until 3 weeks ago I had no clue of modding in Lua or Factorio. In the past i used many of the awesome mods here e.g. LTN, yuoki, Warehousing, ...
In Factorio i like especially the trains and I have a beauty & symmetry OCD. I started modding by dissecting community mods like yuoki's railways mod and others.
Factorio is great game with a great community - and i'd like to give something back.
So here i am with my work in progress mod called 'train engineer'. So far it's working on my test maps. But iam not confident enough in my modding skills and my understanding of Lua to let it loose on the public yet. 
I have a few questions and i need the help of the community and maybe the devs here - see the paragraph 'questions @ forum' further down. The mod in it's current state is attached as a zip. Any help or tips to make this mod better, more stable, more ups friendly or hints/links/etc to improve my modding skills are very appreciated. THANKS!!!>>IMPORTANT:Description:
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You love trains in Factorio? , You don't like loops?, You don't like the look/feel of dual-header trains? You have a beauty & symmetry OCD?
Then maybe Train Engineer is a mod for YOU!
With this mod you get a skilled and fully certified Train Engineer (see https://en.wikipedia.org/wiki/Railroad_engineer). After years of ative duty
Train Engineer Bob has become so skilled his actions seem like magic. He can shunt/switch trains at terminal stations without another track or locomotive.
And he works currently for free.
example for progress of events:
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terminal station
1) =LL-CCCCCCC============== >> train arrives at station (inbound movement)
2) =LL-CCCCCCC============== >> train waits until leave conditions are met
3) Train Engineer Bob does his magic
terminal station
4) =CCCCCCC-LL============== >> train leaves station (outbound movement)
During event 3) to 4):
- mod reads train and copies certain parameters (train composition, carriage types, cargo inventory, fuel of locomotives, loco colors, schedule)
- old train gets removed
- new train gets placed in reversed direction + parameters and inventory is inserted (a completely new train with a new Train id is created!)
Supports:
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- different train composition LL-CCC >> CCC-LL, as long as all locos face the same direction
- fuel + cargo inventory
- schedules
- locomotive colors
- supports base game locomotive, cargo-wagon, artillery-wagon, fluid-wagon
- should support all modded loco + wagons which were derived from the base game entity types and are only modded in the entity prototype >> @me: more testing ...!
>> After every direction change train engineer performs a fuel check on every loco in the handled train. A message is given on the console @ 'fuel inventory < 10 items' and @ 'fuel inventory = 0',
the energy remaining in the burner (fuel bar) is not taken into account
Limitations:
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>> only trains with locos facing in one direction will fire Train engineer event
>> switching trains only at stations with straight rails > no curves or diagonal rails within the length of the train allowed!
>> no cargo-wagon filters or slot filters currently supported
>> trains can not be ridden by passengers
>> trains have to be in automatic mode (mod event hooked on on_train_changed_state with with change from
'train waiting at station until leave conditions are met' to 'path lost' >> which means: single direction train at a terminal station)
>> not multiplayer tested or tested on servers!!!
>> only standard lenght wagons supported (lenght == 6), short wagons like yuoki's 'zement wagons' will fail on Train creation (displacement + not connected)
>> only fluid-wagons with 1 fluidboxes are supported
>> To Do's:
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-- check for incompabilities with yuoki, diesel-loco, ...
-- code optimisation + cleanup
-- Train::id (uint) overflow?! what happens
-- ask in forum for help and optimization
-- big test map >> performance issues?
-- copy_settings(entity) → dictionary string → uint
-- cargo-wagon filters + blocked slots
-- maybe a seperate setting in mods gui for the remaining fuel limit message instead of the fixed 10 items
-- maybe change the fuel check to calculate the remaining MJ in a loco instead of the remaining quantity of the fuel items
-- test if LTN works
-- find out which mod adds the console message 'Warning, a train has no path to station xx' -> it's TheFatController > see ingame setup for 'train has no path'
-- mod setting to mute fuel check messages - otherwise it's spamming the console
-- test all liquids >> water + steam works so far ...
-- basic test with yuoki railway (carriages and locos) seems promising, as long as carriage lenght == 6
>> questions @ forum:
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- what happens at a Train::id overflow? is there a way to preserve the old train id?
- is there a way to safely force passengers off a train which is to be turned around and put them back into the new train?
- is there a clean way to copy settings like inventory filters or blocked slots from a source carriage to a new carriage while the source entity allready got removed via *.destroy() e.g. via a 'invisible dummy train entity'?
As I understand copy_settings() only works with two existing entities.
- in debug mode "F4" >> show-time-usage >> x/y/z >>> what stand z for? Even on a small map z goes up 'linear' to the lenght of just one test train (lenght=15) with z beyond 20++
x/y/z >> is it avg./min./max time? Z this high doesn't seems right! Can anyone point me to informations/guides on how to optimize my code / reduce the time usage?
- volunteer guinea pig to test the mod are very welcome
>> test environment:
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- factorio 0.16.36 win64 steam version on core i7
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- Backup your Saves and mods folder before use!
- use on your own risk!
