Wolmar touches on earlier systems of roads and turnpikes and canals, but really begins with the railway century, with the building of train and tram systems. He then describes the rise of the car, the accompanying roads lobby (in which cyclists played a significant early role) and its dominance over the Department of Transport, the creation of the first motorway network, the closing of tram systems, and the downgrading of public transport more generally.
This trend continued with the 1963 Buchanan report Traffic in Towns, but the failure of attempts to implement it — exemplified by Newbury and London — showed the limitations of road building. The Beeching report of the same year led to the dismantling of much of Britain's railway system (more than half the stations and nearly a third of the track) and despite a subsequent change of sentiment — "railways have cross-party support and investing in them is seen as axiomatic for the growth of the economy" — it has failed to attract adequate investment. Privatisation and enforced competition have not worked well for bus systems, while the absence of tram systems marks a contrast with Europe.
Looking at technological change, Wolmar touches on Uber, autonomous vehicles, and electric cars but argues that "technology has to be the tool of the transport planners, not their master... these ideas do not address the fundamental complexity of transport issues... there is no silver bullet that will simultaneously solve the downsides of transport: congestion, pollution and energy use". And he considers the problems with cost-benefit analyses, especially ones which assume that time spent on public transport is completely wasted, taking as examples "predict-and-provide" road-building and the case of the HS2 London-Birmingham high speed train line.
Wolmar concludes that "it's the politics, stupid". A coherent transport policy "requires a better understanding of what transport is for" (with an emphasis on accessibility rather than mobility), demand management (most importantly through charging for parking and road use), and genuine devolution (including financial independence). He touches in this on the Swiss approach to integrated public transport and the potential for cycling.
Making no attempt to be systematic, Are Trams Socialist? is rather scattershot. Though it doesn't offer much for those already familiar with the subject, however, it does make an accessible and entertaining introduction to the history and politics of British transport.