The new Wales rail franchise holder will be held to account on issues like punctuality, cleanliness and service quality - or they will not get paid.
The head of Transport for Wales (TfW) said the contract includes key elements of service provision not included before.
The winner - also new South Wales Metro operator - is expected to be unveiled in the next 24 hours.
Welsh Government ministers are discussing final details on Tuesday.
The new franchise will come into effect from October 2018, replacing the one run by Arriva Trains Wales for the last 15 years.
Speaking about it for the first time, TfW chief executive James Price said the aim was to "make all parts of Wales more connected".
He said it was more than just rail with buses, park-and-ride, active travel and other modes of transport all important.
It would also go "way beyond" commuting but also travelling for the elderly, for social reasons, for tourism and to access public services.
There will also be a cap on excess profits, with any extra surpluses re-invested in the network.
There are two bidders in the running for the contract:
KeolisAmey - the joint venture company already runs the Docklands Light Railway and the Manchester Metrolink. Keolis also runs Nottingham's trams and claims to be the world's largest tram operator and its major shareholder is the French state-owned railway company SNCF. It operates systems in cities ranging from Melbourne to Boston.
MTR operates the Hong Kong metro - said to be the world's busiest - and a network of 93 stations and 68 light rail stops; also the Crossrail/Elizabeth Line concession in London and is currently running Transport for London rail services.
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The new deal is also likely to involve:
- Taking 124 miles (200km) of track away from the control of Network Rail - enabling a faster investment in new technologies such as digital signalling
- TfW - which oversees the system - would hope to take control of rail-related catering, cleaning, parking and ticketing over time
- £5bn over 15 years of planned investment will see contracts broken up and within the grasp of local, small and medium sized businesses, to make the biggest impact possible on local communities and the economy
TfW said it was a "once in a generation" chance to design a service to meet growing passenger numbers and expectations of more reliable services.
Mr Price said: "This is the first time since devolution Wales has had the opportunity to design something for itself.
"What we've had before was inherited. And many people will have experienced this on a day-to-day basis: turning up at a railway station and not being able to get on the train.
"That's a pretty big disincentive to using it and if you can't get into the centre of a city because the roads are congested as well, that's not an incentive for getting work."
Commuter Regan Cartwright, who travels from Pontypridd every weekday for her job at a Cardiff hotel, said: "Sometimes it's delayed, sometimes it's not - you never know what to expect. I'd like more trains, more carriages, on time - you can never get a seat, it's always rammed."
Jessica Owens normally drives to Cardiff but she sometimes gives herself two hours for the 12 miles (20 km) journey because of "crazy" traffic.
"The only thing that puts me off getting the train is the car park situation," she said. "Driving is cheaper for me. With the train you pay that little bit extra and you get the odd times of day when people are squished together but you don't have the traffic - which is just horrible. "
The decision will be announced to the Stock Exchange and in a statement to AMs.
But details of what the new franchise holder will be offering - and where - including the Metro will not be given this week and are not expected until next month.
It is to allow the losing bidder a 10 day-window to challenge the decision.