.start
{ 
    background: white url('images/start.gif') top center no-repeat;
}

.end
{ 
    background: white url('images/end.gif') bottom center no-repeat;
}
.interchange
{ 
    background: white url('images/interchange.gif') top center no-repeat;
}
.walking
{ 
    background: white url('images/walk_icon.gif') top center no-repeat;
}
.connection
{ 
    background: white url('images/connection.gif') center center no-repeat;
}