# What would be the upper limit in mass/size for land vehicle? **URL:** \ **Category:** Factual Questions\ **Created:** [September 3, 2010, 5:39pm UTC](https://boards.straightdope.com/t/what-would-be-the-upper-limit-in-mass-size-for-land-vehicle/552509 "2010-09-03T17:39:05Z")\ **Posts on this page:** 7\ **Page:** 3
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [September 4, 2010, 4:01pm UTC](https://boards.straightdope.com/t/what-would-be-the-upper-limit-in-mass-size-for-land-vehicle/552509/41 "2010-09-04T16:01:08Z")
> [@qpw3141](#): > > All those of you thinking about stopping the Earth over a significant period of time are missing a very important point: > > You only change the rotation of the Earth whilst accelerating. > > Once you are up to your maximum speed all the energy input from your engines goes to overcoming friction and air resistance. The friction component will simply result in extra heat whilst the air resistance element will result in further turning motion. But, because drag is non linear wrt speed, you’ll need quite a lot of speed to make any difference in anything other than geological time. I guess you’re right. That makes the whole idea of truck with 4/5 of the earth’s mass impractical. ---
**Author:** ![Oregon\_sunshine](https://avatars.discourse-cdn.com/v4/letter/o/50afbb/32.png) [@Oregon\_sunshine](https://boards.straightdope.com/u/Oregon_sunshine)\ **Post date:** [September 4, 2010, 4:18pm UTC](https://boards.straightdope.com/t/what-would-be-the-upper-limit-in-mass-size-for-land-vehicle/552509/42 "2010-09-04T16:18:13Z")
This is why I love the Dope. 😃 ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 4, 2010, 4:20pm UTC](https://boards.straightdope.com/t/what-would-be-the-upper-limit-in-mass-size-for-land-vehicle/552509/43 "2010-09-04T16:20:17Z")
> [@](#): > > I said that the rate of the earths rotation can change without matter being gained or lost, not that angular momentum is not conserved. No, what you said is that it could be done without matter being ejected. The Moon is in fact being ejected by that process; it’s just being ejected extremely slowly. ---
**Author:** ![qpw3141](https://avatars.discourse-cdn.com/v4/letter/q/6bbea6/32.png) [@qpw3141](https://boards.straightdope.com/u/qpw3141)\ **Post date:** [September 4, 2010, 4:26pm UTC](https://boards.straightdope.com/t/what-would-be-the-upper-limit-in-mass-size-for-land-vehicle/552509/44 "2010-09-04T16:26:05Z")
> [@Chronos](#): > > > [@](#): > > > > I said that the rate of the earths rotation can change without matter being gained or lost, not that angular momentum is not conserved. > > No, what you said is that it could be done without matter being ejected. The Moon is in fact being ejected by that process; it’s just being ejected extremely slowly. LOL, yes, looked at that way, it is. 🙂 ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [September 4, 2010, 4:46pm UTC](https://boards.straightdope.com/t/what-would-be-the-upper-limit-in-mass-size-for-land-vehicle/552509/45 "2010-09-04T16:46:10Z")
> [@Sunspace](#): > > [Longest train in the world](http://www.youtube.com/watch?v=9LsuNWjRaAo). An iron-ore train in Australia with eight locomotives and 682 loaded cars … This clearly demonstrates that, so long as trains are accepted, the answer to the OP is “almost arbitrarily large”. That train consists of two locomotives followed by a bunch of cars followed by two locomotives followed by a bunch of cars, etc. There is no reason (other than practicality) why this could not be repeated more or less endlessly, to occupy the entire length of a railroad track that itself occupied much of the land area of the world (with undersea tunnels to add to the available area). ---
**Author:** ![Bearflag70](https://avatars.discourse-cdn.com/v4/letter/b/8e7dd6/32.png) [@Bearflag70](https://boards.straightdope.com/u/Bearflag70)\ **Post date:** [September 4, 2010, 5:51pm UTC](https://boards.straightdope.com/t/what-would-be-the-upper-limit-in-mass-size-for-land-vehicle/552509/46 "2010-09-04T17:51:06Z")
OK, now that we have the technical answer of an infinite train, is there a way we can address the concept more in the spirit of the OP, such as adding continuous tracks to a supertanker ship? ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [September 4, 2010, 10:06pm UTC](https://boards.straightdope.com/t/what-would-be-the-upper-limit-in-mass-size-for-land-vehicle/552509/47 "2010-09-04T22:06:44Z")
> [@Bearflag70](#): > > …such as adding continuous tracks to a supertanker ship? I’m unclear on what this means. Do you mean equipping a ship with tank/bulldozer style propulsion? If so, it probably won’t work well. Any largeish ship depends on support from the water, and would deform/break apart if set on land. Your giant land vehicle will need to be substantially stronger than a ship of the same size. [Previous page](https://boards.straightdope.com/t/what-would-be-the-upper-limit-in-mass-size-for-land-vehicle/552509.md?page=2)