Twenty-four coaches were built for push-pull operation on the suburban rail service including five built to Control Cars (6101–05, 6301–19). Originally used in conjunction with the 121 Class locomotives they were last used with 201 Class locomotives. There were a number of differences between the Irish push-pull Mark 3's and the standard Mark 3's. An underfloor generator, mounted in the Control Car, provided electrical power to the coaches; unlike on the standard Mark 3's, which used a special generator van. This single generator was not as powerful as the two used in the Mark 3 generator vans and was the main reason the sets were limited to 6 cars. Irish Mark 3 push-pull based rolling stock did not have air conditioning and had opening windows instead. There was also a 70 mph speed restriction imposed on the train due to the fact that three of the Control Cars were fitted with LHB bogies from an 8100 Class DART and were air-braked.