It would be fine if engineers, or sturmovie engineers can lay mine: soviet were known to use tons of mine in their defensive operation ( Kursk for example! )
But I like that PTRD team can have this too. But I think it would be interesting if they could lay special mine (like teller mine of PE, or like greyhound mine ) as abilitie: unlike engineers it would be free but has a cooldown ( like every soviet abilitie ).
I was just writing the same thing as Red_Stinger 
Partisans is doctrinal but for now only unit able to blow the bridge. IL2 only with armored targets nearby and way too expensive on CPs...
I also tried PTRD but even with upgrade they don't have mine ability so Soviets can't lay mines. I remember that before it was possible with Ingenery but not now even with upgrade which is strange! I hope this will be solved in 1.10.
Mortar and Satchel combo - it could work (I tried just satchels and they don't) but in combat it is too much to micro I think for 1 bridge. Not to mention that mortar is not able to shoot ground unless upgraded 100 Ammo as precisely Red_Stinger wrote.
Btw PE has Vampire HT which has Goliath underused unit but I usually get one when playing T1. Is good as a radar too. And Brit could do it with Sappers or Commandos.
Lol ^^' I don't wanted to whizz you sorry!
