function rotater()
{
var torotate = new Array('<a href="http://www.cprr.org" target=_blank title="Central Pacific Railroad Photographic History Museum"><img src="imagens/cprr.gif" border="0"></a>',
'<a href="http://www.photorail.com" target=_blank title="PhotoRail"><img src="imagens/photorail.jpg" border="0"></a>',
'<a href="http://www.cprr.org" target=_blank title="Central Pacific Railroad Photographic History Museum"><img src="imagens/cprr.gif" border="0"></a>');

var r = Math.random();
r *= torotate.length;
r = parseInt(r);
if (isNaN(r)) r = 0;
r %= torotate.length;

var result = torotate[r];
document.write(result);
}