Were railway guns ever critical in any battle during WWI and WWII?

Question

Note: this is a question about railway - mounted artillery, NOT about armored trains (which were more akin to tanks-on-rails and had much smaller guns)

The idea behind railway gun is quite sound: a bigger gun is better than a small gun but it is harder to relocate. But if we will use trains, that can carry lots of weight relatively quickly, then we can put REALLY BIG guns on them and move them around with ease!

But the effect is far from expected because the railway artillery requires LOTS of maintenance and logistics, might have problems with aiming in other direction than straight ahead of the tracks and the number of shots per day is simply pathetic:

For example, the famous Dora (no, not that one) required 250 people to assemble the gun in 3 days, 2500 to lay the tracks and 2 flak battalions to protect it from the air attacks and in return, it was providing 14 shots per day.

All this looks horribly inefficient when compared to for example WW II bombers or even smaller, WW I heavy artillery, like the famous Big Bertha (which could fire 8 shots per hour, although indeed with ~7 times lighter shell).

So, were ever those "white elephants" of modern weapons even critical in winning any battle? Or were there just a drain on the resource, that could be better spent on a different kind of weaponry?

Edit:

I've removed the "winning" part since indeed it had not much sense - U-boats were critical in the battle of Atlantic, yet the battle was won by Allies. So in other words, I am looking for battles where railway guns have played a very significant role, no matter on the final outcome.

Answer 1

The only time they were used - although on a different front - they did more or less what they were intended to do.

The German leadership was well aware about the logistical nightmare these guns imposed on the army. The fact that only two were ever ordered shows the over all value even the Germans assigned to these guns. Yet they were deemed necessary to break an eventual stalemate. The super heavy guns like the 80cm "Schwerer Gustav" were purpose built guns to defeat the bunkers on the Maginot line. They were a weapon developed and built for a single purpose - that never came.

The Germans never thought they would rush through France like they did during the Blitz and were rather planning for a prolonged siege like during WW I.

Since they marched through France in mere 6 weeks they were now sitting on now practically obsolete ordnance not knowing what to do with it. When, later on, the German offensive in Russia faced the fortifications of Sevastopol, they actually found a use for the guns they've been sitting on for almost two years.

Sevastopol - on the very edge of the Crimea peninsula - was a major Russian stronghold and hard to conquer since the fortification there were enormous. In the end, not even the large 80cm gun alone could cripple the fortress. A combined effort of the 42cm, 60cm and 80cm guns was needed to knock out the Russian artillery and crippled the fort.

Since the siege itself took more than 9 months to conclude, there was quite enough time to transport and assemble the railway gun there. These super heavy artillery pieces did play a role in defeating the defenses and freed up resources needed on the rest of the eastern front. So while no single piece of equipment can "win" a siege on itself, these guns did contribute - although mainly because the army found an opportunity to use the otherwise useless guns and not because they were such superior equipment.

Answer 2

No, the development of the railway gun came too late. Airplanes could do much the same, far more efficient, and at less cost.

As you said yourself, railway artillery needed LOTS of maintenance. 14 shots per day is not exactly very efficient. Do mind that after 18-20 shots, the barrel was worn out and needed replacement. Before that, each shot would change (widen) the bore diameter. Which required each shot had to be recalculated and adjusted to compensate for that. That (barrel changes) happens with other guns too, but after 500-2000 shots, which is a big difference.

During WW1, there was an excuse: airplanes weren't yet capable of delivering the same amount of bombs on one particular spot. This wasn't the case during WW2. If you needed a lot of ordnance on a particular target, simply use more bombers. Need more impact? Use bigger bombs.

WW1 railway guns weren't really efficient for the investment, but it worked. During WW2 it was a sheer waste of money, time and effort. That's why the allies didn't invest in it. The British used railway guns for coastal defense, but those guns were left overs from WW1 battleships.

The Germans used railway guns to repel the landings at Anzio with moderate success, and the Karl Gerät with more success during the siege of Sebastopol. Looking back, the investments weren't worth it. The few times a railway gun actually made a difference, it could have been done with different weapons are far less cost and effort.