Charles Spurgeon
When preaching and private talk are not available, you need to have a tract ready. Get good striking tracts or none at all. But a touching gospel tract may be the seed of eternal life. Therefore do not go out without your tracts.

Then he said to his disciples, “The harvest is plentiful, but the laborers are few; therefore pray earnestly to the Lord of the harvest to send out laborers into his harvest.”
Matthew 9:37-38