In the midlate 1990s Tomy released a few sets using a "3D Loop" layout that uses figure eight point rails and slope curve rails to make a modified elevated figureeight layout.
In 1995 the Nozomi ThreeDimensional Loop Set (のぞみ号立体ループセット) was released featuring a 2Speed Nozomi and a partiallyelevated figureeight layout. The set also includes a VHS video トミカプラレールたのしいのりものの世界 Tomica Plarail The World of Fun Vehicles. A boxed example of the set can be seen in the Plarail Museum.
Set contentsQuantity 
Item 
Photo 

3 pieces 
2Speed Nozomi 

5  R01 Straight Rail 

5  R02 Half Straight Rail  
12  R03 Curve Rail 

1  R08 Stop Rail 

1 pair  R12 Figure Eight Point Rail  
20 pieces  R18 Slope Curve Rail (four of each A and B slope curves and 12 mini block piers)  
2
pieces 
J03 Iron Bridge sides  
2  J14 Block Bridge Girder  
VHS 
たのしいのりものの世界
A world of fun vehicles 
This initial version of the set included a regular 2Speed Nozomi of the era. Like some other sets with VHS videos in the 1990s, smaller scenery pieces like signals and trees were omitted. I do not have an original copy of this set, but it seems fitting to include it here alongside the other similar sets which I do own examples of. In 1996 the set was rereleased with an additional intermediate car.
Set name  Nozomi ThreeDimensional Loop Set のぞみ号立体ループセット 
Release period  1995 
Train rating  Track rating  
Accessory rating  Overall  
Notes:  The regular Nozomi was used in several sets by this point...  Price  4200 yen (1995) 
In 1996 an updated version of the Nozomi 3D Loop Set with an additional intermediate car was released as the Nozomi 4Car Loop Set (のぞみ号4両編成ループセット). A boxed example of the set can be seen in the Plarail Museum.
Set contentsQuantity 
Item 
Photo 

3 pieces 
2Speed Nozomi 

1  "Plarail" 300 series intermediate car  
5  R01 Straight Rail 

5  R02 Half Straight Rail  
12  R03 Curve Rail 

1  R08 Stop Rail 

1 pair  R12 Figure Eight Point Rail  
20 pieces  R18 Slope Curve Rail (four of each A and B slope curves and 12 mini block piers)  
2
pieces 
J03 Iron Bridge sides  
2  J14 Block Bridge Girder 
In 1996 the set was rereleased with an additional setexclusive Plarailmarked intermediate car. I do have the original intermediate and tail cars as well as the rails and other parts to this set, but it is pictured here with a lessyellowed individual release 2Speed Nozomi as I needed a power car anyways and the original cars are wellplayed. I quite like this PLA RAIL intermediate car, it makes the set more interesting and the train looks cooler, plus it gives a cool variant of 300 series intermediate car.
The figureeight style layout and the way the points interact with trains makes the train switch the direction it travels around each loop each time.
Set name  Nozomi 4Car Loop Set のぞみ号4両編成ループセット 
Release period  1996 
Train rating  Track rating  
Accessory rating  Overall  
Notes:  The unique intermediate car is definitely the highlight of this set, but the cheaper price is nice too  Price  3980 yen (1996) 
In later 1997 the Komachi & Tsubasa ThreeDimensional Loop Set (こまち&つばさ立体ループセット) was released exclusively at Japanese toy store Hello Mac (ハローマック). The set includes mini E3 Komachi and 400 series Tsubasa trains as well as the 1997 connection bar system to connect them together. Although the E3 and 400 series both have reallife connection systems for coupling with other shinkansen trains, the E3 and 400 series themselves did not run together like this.
The background of the box shows the Nozomi Overpass Large Railway Bridge Set which was also released that year. The yellow and red round popout around the box says that solo or connected driving is possible. The yellow oval with blue boarder says it is a Hello Mac  Ace Limited Set (ハローマック・エース オリジナルセット). The back and even some panels on the top of the box show some alternate layouts  I completely forgot to build any of these when I had my copy of this set out to photograph.
Set contentsQuantity 
Item 
Photo 

2 pieces 
2Speed Tsubasa (power and tail car only) 

2 pieces  E3 Akita Shinkansen Komachi (power and tail car only)  
1  Connection joint  
5  R01 Straight Rail 

5  R02 Half Straight Rail  
12  R03 Curve Rail 

1  R08 Stop Rail 

1 pair  R12 Figure Eight Point Rail  
20 pieces  R18 Slope Curve Rail (four of each A and B slope curves and 12 mini block piers)  
2
pieces 
J03 Iron Bridge sides  
2  J14 Block Bridge Girder 
This set includes "mini" versions of the E2 Hokuriku and E3 Akita shinkansens that include only the power and tail cars.
Both trains in my set were produced in June 1997. As this set came out after the Akita Shinkansen Opening Commemorative Set, both trains use the updated 400 series chassis with connection molding.
The set also includes, of course, the same connection piece as the Akita Shinkansen set, allowing the two trains to be connected. I have made a 3D printable version of this connection drawbar which can be downloaded here.
The track in this set is later 1990s production Thailand track, with curve, straight, and figureeight points from toolings originally produced for Japanese manufacturing. The figure eight point rails are the type with tread in most places and roughtop around the directional decider.
Like the other 3D Loop sets, there are not any smaller accessories (this one doesn't even include a VHS tape like the others) but there is a set of iron bridge sides. Obviously the main gimmick is being able to connect the two Shinkansens together or run them separately  like the Akita set obviously it would be cooler if both trains were full size, but it is nonetheless an interesting variation of the threedimensional loop layout sets.
Set name  Nozomi 4Car Loop Set のぞみ号4両編成ループセット 
Release period  1997 (Hello Mac exclusive) 
Train rating  Track rating  
Accessory rating  Overall  
Notes:  I get it, but its too bad the trains don't have intermediate cars...  Price  4800 yen 