Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Class | Wheel arrangement | Fleet number(s) | Manufacturer | Serial numbers | Year made | Quantity made | Quantity preserved |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Mallet and Simple Articulated Locomotives | Mallet and Simple Articulated Locomotives | Mallet and Simple Articulated Locomotives | Mallet and Simple Articulated Locomotives | Mallet and Simple Articulated Locomotives | Mallet and Simple Articulated Locomotives | Mallet and Simple Articulated Locomotives | Mallet and Simple Articulated Locomotives |
| Z | 2-6-6-2 | 3000–3015 | Baldwin | 30566…31557 | 1907 | 16 | 0 |
| Z-1 | 2-6-6-2 | 3100–3105 | Baldwin | 34389…34483 | 1910 | 6 | 0 |
| Z-2 | 2-8-8-2 | 4000–4004 | Baldwin | 34382–34386 | 1910 | 5 | 0 |
| Z-3 | 2-8-8-2 | 4005–4025 | Alco | 52839…62472 | 1913, 1917, 1920 | 21 | 0 |
| Z-4 | 2-8-8-2 | 4500–4503 | Alco | 64373–64376 | 1923 | 4 | 0 |
| Z-5 | 2-8-8-4 | 5000 | Alco | 67578 | 1928 | 1 | 0 |
| Z-5 | 2-8-8-4 | 5000–5011 | Baldwin | 61292…61495 | 1930 | 11 | 0 |
| Z-6 | 4-6-6-4 | 5100–5120 | Alco | 68760–68780 | 1936–1937 | 21 | 0 |
| Z-7 | 4-6-6-4 | 5121–5126 | Alco | 69540–69545 | 1941 | 6 | 0 |
| Z-8 | 4-6-6-4 | 5130–5149 | Alco | 70143…71962 | 1943–44 | 20 | 0 |
Question:
What is the quantity preserved for the serial number of mallet and simple articulated locomotives?
Answer:
Mallet and Simple Articulated Locomotives