Why are electric trams so expensive?

In Manchester (England) we have a tram/light railway system and they recently bought some new units:

According to the link, these cost £2m each. This seems like a huge amount to me (especially compared to, say, a bus, which I know costs a fraction of this). When I was a kid I had a cheap toy train set. The electric motor was simple, why isn’t it a case of just scaling this up? These trams are custom built, so does that account for it or it something more?

Specs. Seems like a pretty high tech piece of engineering.

http://www.flexity2.bombardier.com/pdf/en/Manchester_10474_0209_en.pdf

You’re absolutely correct. In transport discussions, the railfans love to point out that a tram seats twice as many and may last twice as long as a bus. They’re not so keen to point out that the cost is roughly 10 times that of a bus. The reason is a combination of custom fabrication, low production runs, and limited competition.

There are some quasi standard tramcars from Siemens and Alsthom, but still most systems write elaborate specs and insist on their own testing and acceptance. Compare that to the situation with buses, where you pretty much just order some and spec the upholstery and livery colour. Rarely will the factory deliver more than 100 of the same tramcar, so the cost of the jigs and custom fabrication gets spread over fewer units. Off-the-shelf motors or control parts may not meet the authority’s custom specs, and anyway the electric motor manufacturer builds fewer in a year than the diesel engine factory builds in a day.

Finally, we’re down to only four or five manufacturers in the entire world that Western European and American systems feel comfortable ordering from. These companies know they won’t face fierce competition, and that the publicly owned operating authorities are not terribly price-sensitive.

In St. Louis, our light rail system includes tunnels which were built in the 19th century for railroad use. The tunnels have extremely low ceilings, which means the cars had to have specially adapted overhead trolleys to fit. I’d guess that nearly every rail system has some little quirk that requires adaptating a standard design, which drives costs up.

In Rio de Janeiro, the 105 year old “bondjes” are still in service. They were built by Sprage Electric Co. in North Adams, MA.
Boston (MA) bought 80 (massively) defective street cars from Baretta (Italy). So far, these trams have needed repair for brakes, signals, air conditioning, suspensions. Plus, they regularly jump the tracks (cannot cope with the sharp curves).
Funny-the 1938 vintage “president” cars are doing just fine!

The Mancheser system also uses old rail routes, so no doubt there’s some similar quirks. There’s at least one point where signalling is in the hands of the heavy rail operators, for instance (Deansgate Junction signal box controls the Navigation Road level crossings).