The union said late on Wednesday that Deutsche Bahn made a negotiable offer within the allotted time frame, preventing another walkout that would have likely crippled rail traffic again.
But the GDL made it clear that their agreement to suspend strikes did not hold for the private regional competitors of Deutsche Bahn.
If the company failed to “show a serious willingness” to create a basic agreement, further strikes would be scheduled, the GDL said.
Among the deciding components in the offer that brought GDL back to wage negotiations was the willingness to create a collective labour agreement for train drivers across the country.
Despite an improved offer, the two sides still have significant differences, the GDL said.
The union had threatened a further strike on Thursday if Deutsche Bahn failed to make a suitable offer in time.
Strikes by train drivers for both freight and passenger routes have hobbled rail traffic in Germany in recent weeks, with hundreds of cancellations and countless delays reported across the country.
The union, representing 75 percent of Germany's 26,000 train drivers, is pushing for a salary increase for Deutsche Bahn employees and for uniform pay practices at the former monopoly and at competitors.