A brand new word, with two widely variant meanings.
On the one hand, Word Spy (a website for "new" words) describes trolleyology as the practice of a sort of amateur anthropology in which people judge other people based on the contents of their shopping trolleys (shopping carts), especially to provide a means of evaluating potential love interests.
On the other hand, I have seen a reference in The Economist magazine (Feb 23rd, 2008), as well as googled sites such as ZhurnalyWiki or the mckimmy ethics blog where trolleyology is defined as the study of a collection of hypothetical ethics problems au courant in philosophy writing, in which people have to make decisions about switching the routes of runaway trolleys (streetcars) based on variant numbers of lives being at risk. I have run across this practice in my readings in philosophy before, but had never seen it called trolleyology.
It's a good word: so young, yet already deliciously ambiguous! I can already visualize a comedic skit involving people making ethics decisions involving runnaway shopping carts and potential love interests at risk, where the contents of the carts informs the decisions made. Lends a whole new potential meaning to the idea of a "streetcar named desire."
And for some reason I have this vivid image of a trolebus (Spanish for trolley car) in a poem by the neosurrealist poet Miguel Labordeta, but I can't recall the name of the poem or find it using google. But it was a poem definitely linked to mortality and love. So in the spirit of this, I'll quote another poem by Labordeta, "La voz del poeta":
Acariciándolo todo, destruyéndolo todo,
hundiendo su cabeza de espada en el pasmo del Ser
sabiendo de antemano que nada es la respuesta.
En lo alto del Faro.
La voz del poeta.
Incansable holocausto.