Melbourne & Hobson's Bay Railway Co, Geelong & Melbourne Railway Co and Victorian Railways Wagon Physics.
Also best on 4-5ton Wagons, anything lighter or heavier makes it handle different, the friction has been setup so a locomotive of 1,300lbs tractive effort can pull 100 tons.
Notes:
This physic is setup specifically for Victorian Railways rollingstock built from 1853 through to late 1880's and is not compatible with other rollingstock other than the ones built before 1890 as this physic does not have a through brake pipe, if coupled to other stock such as the default wagon that have starting brake cylinder pressure the brakes will not release. You can identify rollingstock with through brake pipe and airbrake by a 'White Square or a White Plus' painted on the frame so I recommend putting wagons at the back of a train to avoid brake problems if you do use them on the mainline and mix them with airbrake stock.