how to get a single data from json from an api

Question

I have trouble understanding how put out a single item from JSON api-

PHP / Json - how do I get to print a single line of data for example just route_type_name":"Train" a working demo is here- https://melbtrip.com/maps/ivanhoe.php

Thank you

Matthew

<?php

$key = ""; // supplied by PTV
$developerId = ; // supplied by PTV

$date = gmdate('Y-m-d\TH:i:s\Z');

//$nearmeurl = "/v3/stops/1071/route_type/0";

$nearmeurl = "/v3/route_types";
?>

<h1>Near Me</h1>
<? 
$signedUrl = generateURLWithDevIDAndKey($nearmeurl, $developerId, $key);
drawResponse($signedUrl);

?>



<? 
//$signedUrl = generateURLWithDevIDAndKey($specificurl, $developerId, $key);
//drawResponse($signedUrl);

function generateURLWithDevIDAndKey($apiEndpoint, $developerId, $key)
{
    // append developer ID to API endpoint URL
    if (strpos($apiEndpoint, '?') > 0)
    {
        $apiEndpoint .= "&";
    }
    else
    {
        $apiEndpoint .= "?";
    }
    $apiEndpoint .= "devid=" . $developerId;
 
    // hash the endpoint URL
    $signature = strtoupper(hash_hmac("sha1", $apiEndpoint, $key, false));
 
    // add API endpoint, base URL and signature together
    return "http://timetableapi.ptv.vic.gov.au" . $apiEndpoint . "&signature=" . $signature;
}

function drawResponse($signedUrl)
{
   // echo "<p>$signedUrl</p>";//
    //echo "<textarea rows=\"40\" cols=\"40\">";
echo "<textarea>";
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $signedUrl); 
    curl_setopt($ch, CURLOPT_TIMEOUT, '3'); 
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    echo $xmlstr = curl_exec($ch); 
    curl_close($ch);
    
    echo "</textarea>";
}
?>