A new train operator began services on the Cambrian Railway.
The new operators of services through Newtown, Caersws and Welshpool are KeolisAmey, working under the Transport for Wales franchise for the Wales and Borders rail services.
They started operating on Sunday, although some services on the line were still affected by the effects of Storm Callum, so it will only be this week that the beginnings of the new service will be seen.
Arriva Trains Wales did not bid for the £5 billion contract. It had held the contract for 15 years.
The new operators say they will renew all rolling stock eventually, which should see new trains on the line.
In the meantime, the existing trains are being rebranded.
New "smart ticketing" is to be introduced and under 11-year-olds will travel for free, with half-price tickets for 16 to 18-year-olds.
Many passengers using the local line have said they hope for more carriages and improved services.
“The big question is how much of a difference will passengers see,” said Russell George, AM for Montgomeryshire.
“The Welsh Government and TFW promised commuters immediate improvement and ‘Transformational Changes.’ We need to see the basics as a start.
“Reliable services, being able to find a seat when you get on, clean trains, assessable toilets, room for bikes, prams etc, access to WiFi and electric sockets.”
KeolisAmey has been given specific targets to meet, these include punctuality and overcrowding, something many passengers on the Cambrian Railway have expressed, particularly at key times and weekends.
"We'll see branding beginning to change, staff uniforms will look different - and over the coming months you'll see new services introduced,” said TFW chief executive, James Price, to BBC Wales.
"Then the next 12 to 18 months, the beginnings of the new rolling stock will come into play."
First Minister Carwyn Jones said: “This is an important moment for rail in Wales – indeed for devolution itself.
"Led by Transport for Wales with our partners KeolisAmey this will be the very first ‘made in Wales’ rail service, designed and delivered by the Welsh Government
"The opportunity to re-design and re-purpose our railway network in Wales is a once in a generation opportunity and I am confident that by 2033 it can be the best passenger rail service in the UK."
