\railalias{percent}{\%}
\railalias{ppercent}{\%\%}
\railalias{underscore}{\_}
\setlength\railextra{3.6ex}
\setlength\railboxleft{0.9ex}
\setlength\railboxright{0.9ex}
\setlength\railovalspace{1.8ex}
\setlength\railframespace{1.8ex}
\setlength\railtextleft{0.9ex}
\setlength\railtextright{0.9ex}
\setlength\railnamesep{0.9ex}
\setlength\railboxheight{16pt}
\setlength\railboxskip{24pt}
\setlength\railtextup{5pt}
\setlength\railjoinsize{16pt}
\def\rail@termfont{\small\ttfamily\upshape}
\def\rail@tokenfont{\small\ttfamily\upshape}
\def\rail@nontfont{\small\rmfamily\upshape}
\def\rail@annofont{\small\rmfamily\itshape}
\def\rail@namefont{\small\rmfamily\itshape}
\def\rail@indexfont{\small\rmfamily\itshape}
\newcommand{\railtterm}[1]{{\texttt{#1}}}
\newcommand{\railtoken}[1]{{\textrm{#1}}}
\newcommand{\railqtoken}[1]{{\rmfamily\textsl{#1}}}
\newcommand{\railnonterm}[1]{{\emph{#1}}}