function foundAnOpeningTag($parser,$tag)
{
    global $inOrigin, $inDestination;

    if($tag=="ORIGIN")
    {
        $inOrigin = true;
    }
    elseif($tag=="DESTINATION")
    {
        $inDestination = true;
    }
}

// Function to handle closing tags.
function foundAClosingTag($parser,$tag)
{
    global $inOrigin, $inDestination;

    if($tag=="ORIGIN")
    {
        $inOrigin = false;
    }
    elseif($tag=="DESTINATION")
    {
        $inDestination = false;
    }
}

// Function to handle characters within tags.
function foundSomeText($parser,$characters)
{
    global $inOrigin, $inDestination;
    global $traindata;

    if($inOrigin)
    {
        $traindata["origins"][] = $characters;
    }
    elseif($inDestination)
    {
        $traindata["destinations"][] = $characters;
    }
}

// Parse the XML.
$parser = xml_parser_create();
xml_set_element_handler($parser, "foundAnOpeningTag","foundAClosingTag");
xml_set_character_data_handler($parser, "foundSomeText");
xml_parse($parser,$response);
xml_parser_free($parser);