Government inspectors have criticised Midland Mainline's new stock of Bombardier trains, saying they do not meet disability standards.
They cited toilet door handles that were too stiff to open, and inadequate colour contrasts in cubicles for those with visual impairments.
Inspectors who examined some of the £160m stock, also said nappy changing facilities were deficient.
Midland Mainline says it is working to correct the problems.
While the train company has described the modifications as "minor", disability groups said small things like colour can make a big difference.