Doubts emerged over the viability of the Maas Line project at the start of last year, when the original budget and timeline was found to be inadequate.
Under the new agreement, the Ministry of Infrastructure will contribute €60m, with Limburg providing €99.9m, Noord-Brabant €36.1m and Gelderland €21.5m.
The completion date has been pushed back from December 2023 to December 2024, although the parties say they hope it will be possible to conclude the works early.
Train operator Arriva Nederland has expressed concern at the delay as it must order new electric trains for the Maas Line by May 2019.
The single-track line is one of the longest and busiest diesel-operated routes in the Netherlands. The electrification project includes raising line speeds by easing curves, closing or modifying level crossings, and constructing three additional passing loops.
Plans for a new station at Grubbenvorst have been abandoned on cost grounds.