I've been following the "Let's Make a Map" tutorial by mbostock about converting files for use for d3.js. I have been able to get things working with files from Natural Earth, but when trying to convert the shapefiles from the MBTA website (http://www.mass.gov/anf/research-and-tech/it-serv-and-support/application-serv/office-of-geographic-information-massgis/datalayers/trains.html), which stores lineshapes with cartesian coordinates and arcs (with topojson -t_srs EPSG:4326...), I get an error:
/usr/local/lib/node_modules/topojson/bin/topojson:303 var i = file.indexOf("="); ^ TypeError: Object true has no method 'indexOf'
I get this even trying different values for EPSG such as 26986. How can I represent these files in d3 (alongside other topojson files that use lat/lon), or convert the coordinates to lat/lon?