25 feet radius curve, Duffield Bank, Plate IV (Minimum Gauge Railways).png
<i>Unknown</i> Engineering drawings are by Arthur Heywood (d. 1916), some photographs may be.<br><a href="//commons.wikimedia.org/wiki/User:Andy_Dingley" title="User:Andy Dingley">Andy Dingley</a> (scanner)
Scan from <cite class="book" style="font-style:normal"><a href="https://en.wikipedia.org/wiki/Arthur_Heywood" class="extiw" title="en:Arthur Heywood">Arthur Heywoood</a> (1898)      <i> Minimum Gauge Railways</i>  <small></small></cite>