[14] Significant expansion of railroads in the 1880s lead to a surge of those employed on the railway lines, including engine drivers, station masters and staff, clerks, labourers and gangers.

[15] That owed a great deal to the hierarchical nature of employment on the railways, with differences being especially pronounced between locomotive drivers, station staff and clerks, and "unskilled" workers.

In 1903, the government of conservative Premier William Irvine sought to stifle the electoral threat of rail workers’ anger at pay cuts by passing of the Separate Representation Act.

The Act barred railway employees from voting in their own electorates, instead being allotted two separate seats in State Parliament's lower house.

[21] The Victorian branch of the ARU was also notable for being one of the few left-wing unions in Australia to have been both captured and subsequently lost by anti-communist elements in the years leading up to the Australian Labor Party split of 1955.

[22] One of the greatest episodes of industrial unrest in the post-World War II history of Australia's union movement took place in 1969 following the arrest and jailing of ATMOEA Victorian Secretary, Clarrie O’Shea for refusal to pay penal fines incurred for striking.

O’Shea, a Maoist aligned with the CPA (M-L), had pursued a campaign of consistent industrial militancy since being elected ATMOEA State Secretary in 1947 to defend and advance his members’ wages and conditions, sick leave and benefits.

Upon his release, O’Shea said, "My release is a great victory for workers...The infinite power of the workers when they are really aroused has frightened the life out of the government and the employers..."[25] The outcome of the general strike was a huge victory both for the ATMOEA and the Australian union movement – while bans clauses remain on the books of Commonwealth legislation, most of the anti-strike penal clauses were abolished in the ensuing years and as a consequence of the strike have never been invoked by the Commonwealth Government in any industrial dispute since.

[26] In 1989 the Victorian Cain Labor Government announced that it would seek to abolish all tram conductors as a cost-cutting measure as part of its effort to arrest the state's fiscal crisis.

At the same time tramways workers occupied and took control of tram depots at Essendon, Brunswick and South Melbourne as part of their effort to demand that Premier John Cain and Transport Minister Jim Kennan to reverse their plans to abolish conductors.

Despite this the ATMOEA did win some concessions as a result of the dispute, with tram conductors being phased out gradually over an 8-year period and many being retrained as ticket inspectors.

[27] Victoria's public transport unions suffered significant losses in size and industrial clout under the State Liberal Government of Jeff Kennett from 1992 to 1999.

It was also during the 1990s that control of the Victorian ARU began to change hands from the old CPA-aligned leadership to a new group of union activists based around the Rank-and-File Committee ticket.

The Victorian ATMOEA experienced parallel changes, with control of the state branch swinging from its old guard Maoist leadership to a moderate-leaning ticket around this time.

Despite these challenges the State Branch's leadership proved successful in making the PTU into a coherent union representing the interests of its members in all areas of public transport.

The PTU and its amalgamated divisions continued to suffer declining membership throughout the 1990s due to job losses in public transport in all states and territories.

Despite the downturn of this period the PTU in Victoria was still able to accomplish significant industrial action, most notably a 48-hour strike during the 1997 Grand Prix weekend in protest at State Government plans to dissolve the Public Transport Corporation.

[31] In March 1998 the PTU chose to rename itself the Australian Rail Tram and Bus Industry Union (RTBU) to reflect the privatisation of numerous public transport services in Australia.

"[33] In October 2012 the union took protected industrial action in Melbourne involving work stoppages in rail operations as part of a campaign by Metro workers against planned changes to their rosters and pay.

The day-to-day operations of the union are broken down into divisions that reflect its members’ different areas of work:[39] • Rail Operations • Tram & Bus • Locomotive • Administration, Supervisory, Technical & Professional • Infrastructure • Fleet Manufacture, Overhaul, Maintenance & Service (Workshops) Each division has its own delegates elected from each worksite who form divisional committees and sub-committees.