De or het railauto?

The correct Dutch article is:

de railauto

How to use railauto

the railautode railauto
this railautodeze railauto
that railautodie railauto
our railautoonze railauto
your railautojouw railauto
every railautoelke railauto
which railauto?welke railauto?
a big railauto / the big railautoeen grote railauto, de grote railauto