To exclude the start and end text...

use strict;
use warnings;

while (<DATA>) {
    if ( /^StartTr1/ .. /^oflTr1/ ) {
        print unless (/^StartTr1/) or (/^oflTr1/);
    }
}

__DATA__
StartTr1
sample 1
sample 1
sample 1
sample 1
SAMPLE 1
oflTr1
nothing
nothing
nothing
StartTr1
sample 2
sample 2
sample 2
sample 2
sample 2
last line before sample 2
oflTr1
junk
junk
junk
[download]

prints:

sample 1
sample 1
sample 1
sample 1
SAMPLE 1
sample 2
sample 2
sample 2
sample 2
sample 2
last line before sample 2
[download]