lastInsertId get from different function - php

Question

I have a form, wich sends information to the database (When filled in)
Form function:
function train_add() {
$sql = "INSERT INTO train_information "
. "(train_id, image, train_name, tare_weight, number_of_bogies, number_of_axles, wheel_diameter_min, wheel_diameter_max)"
. "VALUES (train_id, :image, :train_name, :tare_weight, :number_of_bogies, :number_of_axles, :wheel_diameter_min, :wheel_diameter_max) ";
$sth = $this->pdo->prepare($sql);
$sth->bindParam(':image', $_POST['image'], PDO::PARAM_STR);
$sth->bindParam(':train_name', $_POST['train_name'], PDO::PARAM_STR);
$sth->bindParam(':tare_weight', $_POST['tare_weight'], PDO::PARAM_STR);
$sth->bindParam(':number_of_bogies', $_POST['number_of_bogies'], PDO::PARAM_STR);
$sth->bindParam(':number_of_axles', $_POST['number_of_axles'], PDO::PARAM_STR);
$sth->bindParam(':wheel_diameter_min', $_POST['wheel_diameter_min'], PDO::PARAM_STR);
$sth->bindParam(':wheel_diameter_max', $_POST['wheel_diameter_max'], PDO::PARAM_STR);
$sth->execute();
return $this->pdo->lastInsertId('train_id');
}
Right. So when the form is filled in, it is send to the database (works).
The user will be redirected in 10 seconds (Did this for myself to see if any errors come up).
<?php
//Train information is send to the database, and selects the ID of the just added train//
$add_train = $database->train_add();
?>
<meta http-equiv="Refresh" content="10;url=http://localhost:8080/show_axle_table.php?train_id="<?php ['$id'] ?> >
show_axle_table.php:
<?php
$show_axle = $database->axles();
?>
<div id="train_select_table">
<table>
<tr>
<th>Train id</th>
<th>Number of bogies</th>
<th>Number of axles</th>
</tr>
<div id="loopRow">
<?php
foreach($show_axle as $res){
//Loop trough results, generate a tablerow every time
?>
<tr>
<?php
echo "<td>" . $res['train_id'] . "</td>";
echo "<td>" . $res['number_of_bogies'] . "</td>";
echo "<td>" . $res['number_of_axles'] . "</td>";
?>
</tr>
<?php
}
?>
</div>
</table>
</div>
And the function:
function axles(){
$id2 = $this->train_add($id);
$sql = "SELECT * FROM train_information WHERE train_id = '$id2'";
$sth = $this->pdo->prepare($sql);
$sth->bindParam(":id2", $_GET["train_id"], PDO::PARAM_STR);
$sth->execute();
return $sth->fetchAll();
}
Now the table shows me a ID of a train. But it adds 1 so everything else is empty.
For example:
User fills in form. Sends it to Database (train_add) It gets and id of 1 and is done.
Then the page redirects to the show_axle_table.php. Function should get the last inserted id. but it shows me a ID of 2.
Also i want the ID to be shown in the top of my page like:
show_axle_table.php?train_id="<?php ['$id'] ?>
But right now it shows nothing. (train_id=)

Answer 1

Update like this:
<?php
//Train information is send to the database, and selects the ID of the just added train//
if (!(isset($_GET['train_id]) && $_GET['train_id'])) {
$add_train = $database->train_add();
}
?>
<meta http-equiv="Refresh" content="10;url=http://localhost:8080/show_axle_table.php?train_id="<?php echo $add_train; ?> >
<?php
$show_axle = $database->axles($_GET['train_id']);
?>
<div id="train_select_table">
<table>
<tr>
<th>Train id</th>
<th>Number of bogies</th>
<th>Number of axles</th>
</tr>
<div id="loopRow">
<?php
foreach($show_axle as $res){
//Loop trough results, generate a tablerow every time
?>
<tr>
<?php
echo "<td>" . $res['train_id'] . "</td>";
echo "<td>" . $res['number_of_bogies'] . "</td>";
echo "<td>" . $res['number_of_axles'] . "</td>";
?>
</tr>
<?php
}
?>
</div>
</table>
</div>
And function as
function axles($id){
$sql = "SELECT * FROM train_information WHERE train_id = '$id'";
$sth = $this->pdo->prepare($sql);
$sth->bindParam(":id2", $_GET["train_id"], PDO::PARAM_STR);
$sth->execute();
return $sth->fetchAll();
}