In terms of expense, genuine Light Rail only wins when a city is on a level plain, with wide streets and many alternative routes. When its exponents speak of ‘Light Rail’ being cheaper, their argument is based on the track record in such cities with 100%-separated LR, rather than trams posing as ‘Light Rail’ while sharing the streets. Sydney’s trams have imposed a heavy tax burden
(“Sydney light rail bill passes $3 billion...”; click photo for more...):

But Suspension Monorail  wins - cost-wise - in small cities like Wellington, with many hills, narrow streets, and very few alternative routes. It requires no tunnels and virtually no digging up of roads to reposition underground services - both factors that make all the difference in terms of cost. See also our FAQ page about Construction, and our more detailed Facts page re Costs.