The event is being backed by the Cardiff Blues, with special prizes on offer for those taking part.
Sergeant Jaci Thomas, who leads BTP's Neighbourhood Policing Team (NPT) in Pontypridd, said: "With the onset of warmer weather and lighter nights, Easter is a time when, traditionally, incidents of anti-social behaviour, trespassing, stone throwing and vandalism increase.
"This has certainly been the case in the past, with the three valleys north of Cardiff covered by our NPT - the Aberdare, Merthyr and Rhondda valleys - historically seeing an increase in reported crimes along the rail network at this time of year.
"The vast majority of these offences are committed by young people of secondary school age. With this in mind, we've decided to run a rail safety campaign over the Easter break to tackle these issues head-on and deal with them before they arise.
"The key aim is to promote railway safety and make people aware of the very real consequences of trespass and anti-social behaviour. This early intervention will hopefully make them less vulnerable to making bad decisions and, subsequently, less likely to get involved in criminality."
Teaming up with BTP throughout the week will be a number of local sports clubs, the Army, Scouts, rail industry partners Network Rail and Arriva Trains Wales, as well as other members of the emergency services.
Taster events and tutorials will be put on by the partner agencies, while each event will culminate in a 5-a-side football tournament or touch rugby games involving all the youngsters who attend.
Those who take part could be in with a chance of attending a Cardiff Blues match as a guest of the rugby side, where they will meet some of the players and coaches.
"While rail safety is obviously at the heart of these events, it is also a great opportunity to access local activities, services and available support while having plenty of fun during the sports," said Sgt Thomas.
"This is a collaborative forum and the support for this event from a vast number of agencies throughout the area reflects the positive engagement our Neighbourhood Policing Team has in the communities of Rhondda Cynon Taff."
Events will take place at the following venues:
Ystrad Rhondda Sports Centre - Monday, 25 March, between 1100 and 1300
Aberdare Leisure Centre - Tuesday, 26 March, between 1100 and 1300
Merthyr Tydfil Leisure Centre - Thursday, 28 March, between 1100 and 1300
Hawthorn Leisure Centre, Pontypridd - Wednesday, 3 April, between 1100 and 1300
The following partner agencies are involved in the project: Network Rail, Arriva Trains Wales, South Wales Police, the Scouts, Army/Cadets, fire and rescue service, Dan (substance misuse advisors), Cardiff Blues, Cardiff City Football Club, The Prince's Trust, St John Ambulance, Samaritans, StreetGames sports charity, various local sports clubs.