Abstract: The preferred embodiment of the invention disclosed herein relates to a toy system comprising a generally closed track arrangement and a toy vehicle adapted to be propelled in the track by a pressurized fluid. The track arrangement is preferably a series of transparent tubular members interconnected to form any desired track configuration. One of the tubular members includes a pressurized fluid inlet opening adapted to be coupled to pressurized fluid source and further includes check valve means and an exhaust opening. The check valve means is located on the upstream side of the inlet opening and closely adjacent thereto; the exhaust opening is located on the upstream side of the check valve means and is closely adjacent thereto. The toy vehicle can be in any desired shape loosely fitting within the tubular members and includes, at its tail end, flexible seal means which engages the inner periphery of the tubular track members to prevent the flow of pressurized fluid around the vehicle.