Shalom HaRav Kornfeld shlita,
I have a random question about Techum Shabbos.
I am familiar with the unsolved question as to whether there is an issur techumim above ten tefachim.
But what about below the ground, let's say, walking through a tunnel.
Is there any discussion anywhere about whether the issur applies there?
(I also know that the techum is measured by going through mountains etc. which might be viewed like a tunnel, but here I am referring to actually under the ground)
The question is relevant to a Haftara shiur that I am writing.
Thank you very much,
Moshe Dovid
Just to make an initial comment. It seems that there could not be a Torah prohibition of Techum in a tunnel. This is because Shulchan Aruch Orach Chaim 404:1 states that there is no techumin deoarisa in a sea or river, because the latter are not similar to the "Diglei Midbar"; to the way the Bnei Yisrael were when living around the flags in the wilderness. Now, the Gemara Shabbos 98a states that if one carries 4 amos in a covered public domain one is exempt because this is not similar to the Diglei Midbar. We learn that a crucial characteristic of the set-up in the desert is that it was open to the sky. Since techumin also must be similar to the Diglei Midbar for there to be a Torah prohibiton, it follows that the latter could not apply to a tunnel, since it is covered over.
KOL TUV
Dovid Bloom
Sources from Mishnah and Gemara about caves:-
1) In the Mishnah 61a we find a dispute between Chachamim and Rabbi Akiva concerning somebody who was in a small city and placed his Eruv in a big city, or vice versa. Chachamim maintain that the Eruv enables him to walk through the cities, plus an additional 2000 amos. R. Akiva said that he is only allowed to walk 2000 amos from where he placed the eruv. R. Akiva argued against the Chachamim "Do you not agree to me that if he placed his eruv in a cave, that he is only allowed to walk 2000 amos from where he placed the eruv?!". The Chachamim replied to R. Akiva that the latter is only true for a cave where there are no inhabitants, but if people live in the cave, he is allowed to walk throughout the entire cave, plus an additional 2000 amos from the end of the cave.
2) On 61b the Gemara cites a braisa that if one was inside a cave when Shabbos commenced; even if this cave was as big as the cave of Tzidkiyahu, the King of Yehuda; one may walk throughout the entire cave on Shabbos, plus an additional 2000 amos. The Shulchan Aruch Orach Chaim 408:2 writes that if one places the eruv in a private domain, even if this was a country as big as Ninveh; or if one placed the eruv in a cave fit for dwelling; one may walk through the entire area plus another 2000 amos.
3) We learn from these sources that a cave is considered as a Reshus Haychid if it is fit for living. This is also stated by the Maharam to Tosfos 42b DH veKaltah; that the entire cave is considered as 4 amos, so one may walk through it.
4) If we assume, for the time being, that a tunnel is the same as a cave, then we see that if one was in the tunnel when Shabbos started; or one put one's eruv there; one may walk freely in the tunnel.
Chodesh Tov
Dovid Bloom
Further reply:-
1) There is another important Gemara in Eruvin 44b where Abaye said to Rabah "If somebody was inside a cave which was 4000 amos long; and on the roof it was less than 4000 amos long; would he not be able to walk through the entire cave plus 2000 amos outside it?!". If one looks carefully at the Gemara, one sees that it is only inside the cave; plus 2000; that one may walk freely, but the cave and the rest of what is surrounding it, are not necessarily connected.
[ I want to refer us to 2 other places in the Gemara; where we learn, in totally different areas of Halacha; that the undeground is considered as being a separate place from the overground. The first is in Peaschim 86a where Rabbi Yochanan said "Mechilot Lo Nitkadshu"; the underground parts of the Beis Hamikdash do not possess the same holiness as the overground parts. The other source is from Makos 12a where Rav Sheshet said "Lo Nitzrechu Ela LiMechilot". Rashi DH LeMechilot writes that this means that when the inadvertent Rotzeach goes into exile, he cannot live underground inside the boundaries of the Refuge City. Similarly, in Eruvin, one can walk freely inside the tunnel, but this does not mean that it gives you the right to walk freely on top of the tunnel - DB].
2) Now we skip to the Chazon Ish Orach Chaim 110:28 DH Nireh deIr who writes that if a city is built upon pillars which are 10 tefachim high above the earth, the area beneath the city does not possess the same Din as the city. If there is a house beneath, one measures the Techum of this house from the the house, and it does not possess the same Techum as the rest of the city above. Chazon Ish writes that in the same way that a cave does not make what is on top of it into a city, so too a house 10 tefachim higher up, does not make what it is below it into a city.
[ I think that this is consistent with what I wrote above that the cave is separate from what surrounds it - DB]
3) This is going to be important, bs'd, in the discussion concerning what is the din of an underground railway.
Yasher Koach
Dovid Bloom
The London Undergound:-
1) In Teshuvat Sheivet Halevi 6:48, Rav Yehudah Aryeh Dunner, shlita, asked Rav Wosner zt'l a question concerning the Halacha if people in London have to go to hospital on Shabbos for Pikuach Nefesh. Rav Dunner suggested that it might be better to go to hospital overground by taxi, because if one goes underground; since there are no dwelling houses there it follows that the Underground is outside the Techum Shabbos, so if there is a choice of going in a taxi, that would be preferable since that way one remains inside the Techum. Rav Dunner cited the proof from Eruvin 44b (that I mentioned in item 1 of my 3rd reply) that we see that if there is a cave where people live underground, one is not allowed to walk on the roof of the cave more than 2000 amos, because inside the cave is a totally different domain from the roof.
2) Rav Wosner replied that Rav Dunner's argument is not consistent with the Halacha. He cited the Ritva on 44b who writes that inside the cave is entirely Reshus HaYachid, whilst on top of the roof of the cave is totally Reshus HaRabim. We see that the cave and the roof on top, are totally different domains. Rav Wosner asserts that the Underground is different because the area below ground is also part of the city, and is used by the city's population so it belongs to the Techum.
3) Sheivet Halevi then cites the Chazon Ish that I mentioned in my previous reply, item 2). However he concludes that the city-dwelllers use the area under the city for their needs, so the reality is that the Underground territory is part of the city. Rav Wosner writes that it is very obvious that the Underground is entirely part of the city, just as much as the houses are, so the Techum of Shabbos is measured from the last houses. He concludes that one may travel on the Underground; for Pikuach Nefesh; even if it is possible to travel overground.
Dovid Bloom
Rabbi Shimon bar Yochai's network of tunnels in Northern Eretz Yisrael:-
1) I found, bs'd, that Tosefta Eruvin 4:8 states that Rabbi Shimon said "I myself have the capability that people could go up from Tiberia to Tzipori and from Tzor to Tzidon because of the caves and towers between these places".
The Rosh, in chapter 5 of Eruvin, near the end of siman 3, cites a similar statement from Talmud Yerushalmi Eruvin 5:1 where Rabbi Shimon bar Yochai said "I am able to make it that they can walk from Tzor to Tzidon and from Tiberia to Tzipori through caves and through Burganin".
2) I have not been able to find a lot of explanation of the Tosefta and the Yerushalmi in the Mefarshim. I did see that the Pnei Moshe and the Korban HaEidah, on the Yerushalmi. write that the Yerushalmi is proving from the statement of R. Shimon bar Yochai that the boundary of a city can be extended by more than 2000 amos.
3) It seems to me that we learn from the Yerushalmi that a tunnel does not have the same Techum as the city, but rather it possesses its own Techum. It is a Reshus Hayachid and one may walk through it. We should note that Rashi Shabbos 19a DH uMiTzor writes that it takes a day to go from Tzor to Tzidon. [Nowadays it takes about 8 hours to walk between these 2 places, which is a full days walk -DB]. But R. Shimon bar Yochai tells us that one can walk in the tunnels between Tzor and Tzidon on Shabbos.
[ 4) Possibly this can also help us to understand the Gemara Shabbos 104b where Rabbi Ami said that if one wrote one letter in Tiveria and one letter in Tzipori one is liable for the Melacha of writing 2 letters. How could a person go from Tiveria to Tzipori on Shabbos? The answer is that he went through the tunnels and this is permitted. The only prohibition that he transgressed is writing 2 letters - DB]
Good Shabbos
Dovid Bloom