\usepackage{tikz}

\mode<presentation>

\setbeamertemplate{title page}
{
	\usebeamerfont{title}{\usebeamercolor[fg]{title}\inserttitle}\par
	\usebeamerfont{subtitle}{\usebeamercolor[fg]{subtitle}\insertsubtitle}\par
  \bigskip
  \usebeamerfont{title}{\usebeamercolor[gray]{title}\hrulefill\par}
	\bigskip
	\usebeamerfont{author}\insertauthor\par
	\usebeamerfont{institute}\insertinstitute\par
	\usebeamerfont{date}\insertdate
}

\setbeamertemplate{section page}
{
    \begingroup
    \usebeamerfont{section title}\insertsection\par
    \endgroup
}
\AtBeginSection[]{%
  \begin{frame}[plain]
    \usebeamertemplate{section page}
  \end{frame}
}

\mode<all>
\endinput