A push joint adapter is connectable to one or more push joint pipe fittings in a pipeline. The push joint adapter includes an insertion section insertable into a socket of a push joint pipe fitting in an interference fit, a pipeline section connectable with the pipeline, and a collar disposed between the insertion section and the pipeline section. A restraint ring assembly cooperable with the push joint pipe fitting includes a restraint ring secured to the pipeline section and engaging the collar and a restraint rod connected to the restraint ring. The push joint adapter facilitates connecting push joint gasketed bell gate valves and fittings in a pipeline such as a polyethylene pipeline.