The Republican leader's remarks highlight the unusual political divisions on trade.
The Senate passed the Iran legislation last week.
"I would think that we would want to increase Amtrak's budget," Sen. Bill Nelson said.
Sen. Barbara Boxer called the legislation an insult "to women everywhere."
The vote follows a vote on Loretta Lynch's attorney general nomination last month.
The battle over trade comes as Democrats have floated a potential deal.
Jordain Carney 05/13/15 11:44 AM EDT
"It’s not going to happen," Sen. Bob Corker said.
By Alexander Bolton and Vicki Needham 05/13/15 10:51 AM EDT
They are pushing the GOP for a stand-alone vote on currency manipulation.
The Senate majority leader sent his condolences to the victims.