I have been playing with the snapshot and it seems that placing a redstone torch next to a block of tnt will not set it off. It won't affect rail junctions either.

When i place a redstone torch next to a junction rail it usually switches.
When i place a redstone torch next to a block of tnt it shoudl set it off.

The junction rail did not flip but instead stayed the same.
The tnt did not activate

1. Create a rail junction
2. Place a redstone torch next to it
3. Stare as it does not change.

1. Place tnt
2. Place redstone torch next to it.
3. Watch as it does not blow up in your face.