Oscar Puente is set to appear late on Tuesday before the Permanent Deputation, a reduced caretaker legislature that holds limited powers between parliamentary terms before Spain's general election on November 29.
Calls for Puente's resignation have included from coalition allies, in the wake of Wednesday's high-speed collision.
With a confirmed death toll of 69 so far, it was the second accident on the same line this year after a crash in January that killed 46 people.
Puente has refused to step down, saying his way of taking responsibility was to "face up" to the crisis by explaining what happened to the public and fixing the system.
On Monday, Prime Minister Pedro Sanchez said the government would approve an aid package doubling payouts for crash victims, advancing compensation payments and improving temporary incapacity cover.
Sanchez said the priority was helping victims and "restoring the shattered confidence in high-speed rail as soon as possible with whatever it takes".
After cabinet meets on Tuesday to approve the package, Puente is expected to present new safety measures.
Spanish newspaper El Pais, citing unidentified sources, reported the measures being considered included imposing a 40km/h speed limit when relying on a driver's vision to see obstacles ahead if a signal system fails.
Spain would push for a faster rollout of the standardised European Rail Traffic Management System for safety and signalling across its network, the report said.
Implementation of the system is behind schedule on the line where the accidents occurred, government contracts show.
Other measures included hiring more staff and improving conditions in rail control centres, the report said.
Puente said on Friday a computer failure knocked out the signalling system and a subsequent control-centre order for the train to resume its journey was "inexplicable".
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