Petition Ban booking assistance onto trains

The elderly and disabled have to book assistance on and off trains in advanced, the suggested time is at least 24 hours ahead of the journey. This often makes days out tricky as everything has to be planned to ensure that the person in question gets to the station in the preplanned time for their assistance.
I feel this is unacceptable in this century, why should people control their days out and predict when they want to return purely for the railways ease. Wheelchair users are also unable to acces the majority of tubes therefore it is impossible to estimate the amount of traffic and how long it will take them to return to the station.
The government should Implement a legislation to ensure that those of us with impairments can travel with as much ease as our peers. All trainlines should be able to support us on and off trains when we need the help, not when it suits them. And new trains should have a automatic ramp built into at least one carriage by law.