Rail operator Northern is to introduce the scheme on routes affecting Doncaster, Sheffield and Barnsley from August 28 - which could see passengers stung with fines if they are found travelling without a ticket.
The routes where the penalties will come into effect are the Doncaster-Leeds line, which includes Bentley and Adwick stations, routes from Sheffield to Wakefield and Huddersfield via Barnsley and the line between Sheffield and Nottingham which includes Chesterfield and Dronfield.
It means that if passengers get on trains without a ticket at stations where ticket buying facilties are available they may be liable to a penalty fare.
A Northern Rail statement said: "If a passenger gets on a train without a ticket or Promise to Pay notice at a station where ticket buying facilities are available, they may be liable to pay a penalty fare.
"The penalty is the greater of £20 or twice the full single from the station where they got on the train to the next station at which the train stops. If the passenger wants to travel beyond the next station they must also pay the relevant fare from that station to their final destination."
Examples of when a Penalty Fare may be charged:
• travel without a valid ticket
• are unable to produce an appropriate Railcard for a discount ticket
• are aged 16 or over, travelling on a child rate ticket
• travel beyond the destination on your ticket
The statement added: "Reducing the number of people who travel without a ticket is not only in our interest as the operator, but also in the interest of our fare-paying customers.
"Few of us want to pay more for our tickets because some people avoid paying, and the loss of income due to people travelling without tickets reduces the money available to invest in a better rail service."
Passengers are being advised to buy tickets or Promise to Pay notices before boarding trains - otherwise they may be penalised.
A Promise to Pay notice is a ticket that must be obtained from ticket vending machines if customers do not have the facility to pay by credit/debit card.
The notice allows customers to board the train with the intention of exchanging the notice at the first opportunity with a revenue officer, or at the next available booking office.
Added the statement: "If you board a train without a valid ticket or Promise to Pay notice you may have to pay a Penalty Fare. If it is shown that your intention was to avoid your fare, then you are breaking the criminal law and you may be liable for prosecution."
If you travel on the railway with the intent of avoiding paying the fare, the current maximum penalty upon conviction is a £1,000 fine and/or three months imprisonment.