1948's Prop. 3 changed the number of brakemen/flagmen required per train by the Collective Bargaining Agreement. Voters approved it by 51%.

1964's Prop. 17 eliminated the CBA requirement to have a fireman on other than diesel-operated trains carrying passengers. (It had already been established not to have a fireman on passenger trains operated with a Motor Car or RDC.) It was approved by 61% of the voters, and in effect allowed for railroads in California to eliminate the fireman's position on most or all freight trains and yard jobs, subject to specific Local or System Agreements. For example, in 1972 the UTU-E negotiated what was called the "Manning Agreement" on Southern Pacific's Western Lines.

Source: [www.sos.ca.gov]

It's always been interesting to me that both of these Propositions were really Collective Bargaining issues, yet the railroads were able to circumvent that by going the legislative route.