Sandilands was the first member of ParalympicsGB to claim a medal on day nine in Paris.
The Scottish Paralympic debutant won the men’s T20 1500m by more than four seconds. In doing so, he broke the world record, previously held by Michael Brannigan of the USA by a tenth of a second, in a time of 3:45.40.
ParalympicsGB’s second medal on the track was won by Perrineau Daley, 35. Another Paralympic debutant, he crossed the line in 17.27 seconds, just over half a second behind Belgian winner Maxime Carabin.
In the women’s T20 1500m final, Hannah Taunton finished in fifth place, missing out on a medal by just over nine seconds.
Jonathan Broom-Edwards missed out on a medal in the men’s T64 high jump final, finishing in fifth place with a best completed jump of 1.89m.
Transgender athlete Valentina Petrillo is through to the semi-finals of the T12 200m after finishing third in her heat.
The 51-year-old Italian finished with a season best time of 25.95, just over half a second behind Simran of India, to qualify for the semi-finals, which take place at 18:42 BST on Friday. The final is at 18:33 on Saturday.
On Monday, Petrillo failed to reach the T12 400m final after finishing third in her semi-final despite recording a personal best time of 57.58.