Trott won silver in the women's omnium, having been unable to overturn the unassailable seven-point lead of Sarah Hammer of the USA.
Becky James then took Team GB's medal tally to five for the championships, with a bronze in the women's keirin. The 22-year-old from Abergavenny in Wales had had to go through the repechage to even make the semi-finals after being relegated from a winning position in her heat for leaving the sprinters' lane.
Britain's final overnight chance of a medal was in the men's Madison event, through Jon Dibben and Owain Doull.
Despite high hopes, triple Olympic champion Jason Kenny was among those to face a return without a podium appearance as GB drew a blank on the penultimate day.
The 25-year-old from Bolton had to settle for a hat trick of fifth-place finishes after his quarter-final elimination in the sprint by France's Francois Pervis, who had won two gold medals and was on course for another overnight. GB's Ed Clancy had finished fifth in the men's omnium.
Britain's women missed out on a medal on day four, with Jess Varnish and Katie Archibald fourth in the women's sprint and points race, respectively, and neither could add to their tally yesterday.
Archibald, the 19-year-old from Milngavie, the team pursuit world champion on day two, put in a gutsy display in just her fourth international points race. She was one of seven riders to gain a lap - and with it 20 points - on the field, but was squeezed out of contention as Amy Cure of Australia won gold.
Archibald, making her world championships debut this week, said: "Fourth is a positive for me, but it's a shame. You could argue it was close, but it wasn't close. I didn't have it."