First of all, I would like to point out that my proposal includes some of the solutions already proposed, such as the construction of a new freight railway line from Ljubljana to Kranj with a connection to Brnik Airport, a new Ljubljana railway station with a higher capacity, a separate freight line lowered two levels below the main station and the lowering of the passenger railway lines in the vicinity of the centre of Ljubljana one level underground.
In addition to the above solutions, I propose upgrading or building new passenger lines in the vicinity of Ljubljana to speeds of 160km/h and a correspondingly smaller number of stations (marked with larger circles in the annex). This would separate passenger rail traffic from freight traffic and allow for higher capacities for both the main freight lines (red in the annex) and the passenger lines (yellow), and in the area of concentrated population in Ljubljana, the Ljubljana Metro would run on the passenger line (smaller circles in the annex). The larger stations would be designed as park & drive, i.e. you could drive to the station, park and transfer to the train, and with increased speeds and direct lines, the train would be the fastest option and a tempting alternative.
My personal opinion is that the proposed expansion of the AC sections near LJ to six lanes is a waste of money and will not solve traffic congestion, it will only divert more migration to the roads (for those who are interested in more, you can read what induced demand is and how it affects the roads), as traffic congestion on the roads is a reflection of poor rail infrastructure and lack of alternatives, not poor road infrastructure. Building two extra lanes of road increases capacity by around 2000 vehicles in one direction in one hour, by comparison a double-track railway can carry over 20000 passengers smoothly in one hour.
I would also mention that the Ljubljana rail network is part of several corridors and could use a lot of EU funding to renew the lines, and that it is the busiest network in Slovenia and therefore needs to be upgraded, but it is also the most profitable sections.