I finished the first part at the rebuilt northern portal of the Gotthard Tunnel. The railway line reaches its summit at 1,151 m above the sea shortly before the southern portal at Airolo. The latter changed, too: a road was routed above the exit, thus the nice masonry portal disappeared behind ugly concrete. The changes to the portals lengthened the tunnel from the original 14,982 m to the current 15,003 m. The valley of the Ticino descends towards the east-southeast, thus the tunnel exit is a sharp curve.

Tilting train SBB RABDe 500 009 "Friedrich Dürrenmatt" on a northbound InterCity-Neigezug (ICN) service is about to enter the Gotthard Tunnel on a sunny evening
At the other end of Airolo (1,142 m above the sea), there is a valley step, where the river drops about 100 metres in elevation in the Gola di Stalvedro (Stalvedro Gorge). Just before, the railway changes to the other side of the valley, with an 83 m viaduct above the Ticino. As on the north ramp, most of the original steel bridges of the southern ramp have been replaced by masonry bridges in the last century.

On the bottom left of this downriver valley view with the village of Madreno, an SBB Re 620 (Re 6/6) and an SBB Re 430 (Re 4/4III), a common pairing for the Gotthard route also dubbed "Re 10/10", exits a tunnel and arrives on the viaduct with a northbound container train
Along the next flatter and wider section of the valley, the railway curves along the southern valley side.

Another SBB RABDe 500 on a southbound ICN service recedes after having met my northbound InterRegio (IR) limited-stop regional train
The next, twice as big valley step starts at Rodi-Fiesso, below the old roadside hotel of Dazio Grande, in quite dramatic fashion: the river disappears into a gorge, the railway (paralleled by the old road) crosses it at the end of a curve, and the highway passes in the opposite direction underneath. What's also worth to note on the photos below is that the managers of SBB still aren't completely enamoured by the notion of "corporate identity": most old locos still sport their 1970s–1980s liveries and even their original numbering and names in metallic letters.

Above: another "Re 10/10" (led by SBB Re 620 082 = Re 6/6 11682 "Pfäffikon SZ") just passed Rodi-Fiesso station with a southbound intermodal freight train
Below: SBB Re 420 206 (Re 4/4II 11206) with a northbound IR left the point where all roads cross

Immediately after, there is a tunnel.

Above: an SBB RABDe 500 on a southbound ICN service recedes towards the gorge
Below: the same train seen through the tunnel

While the river plunges into the Gola di Monte Piottino (Gorge of Mount Piottino; see in my Summer Holiday Photo Blog contribution), the railway scales most of the 200 m height difference of the valley step in two spiral tunnels. After the 1,568 m long first one, in the north valley side, the line crosses the river in cuttings across the top of the rocks of the gorge.

Having passed the embankment on the right in the middle of the picture a minute earlier, tilting train SBB (formerly Cisalpino) ETR 470 002 on a southbound EC service (towards Milan) left the bottom portal of the spiral tunnel and passes the bridge above the gorge
There used to be a level crossing here (in place of the road overpass I made the photo from), with the guard's abandoned house still standing. That's where I fled when a storm arrived the previous day, but it was no use as the thunder and heavy rain was unabated for two hours when I couldn't wait any longer and ran up to Dazio Grande to catch a bus.
About a kilometre down the valley, there is the 1,567 m long lower spiral tunnel, and immediately after, the line returns to the north side of the valley on a 103 m viaduct. An interesting oddity is the short tunnel for one track only (which unfortunately was closed for maintenance when I was there). From the Gotthard trail that runs high above, there is a beautiful view on all of this and even the upper level of the previous spiral (though the bushes below the trail would need a clearing).

An SBB Re 460 with a southbound IR left the bottom of the lower spiral tunnel, with the portal of another tunnel on the upper level also visible on the left. In the background upper right, the brownish inverted triangle with a white line on top is the same masonry embankment beyond to the upper portal of the upper spiral tunnel which is also on the previous photo
One of the construction bases of the GBT (from where the tunnel is accessed via an intermediate access shaft) is just downriver from the viaduct on the above photo. Shortly after, snaking along the bottom of the northern valley side,the line arrives in the station of Faido, the only intermediate station along the southern ramp still served by the limited-stop regional trains since all-stopper trains were "replaced" with buses in 1994, a measure then justified with the need for more line capacity for through trains. (Since the end of 2010, there is again one pair of commuter trains with additional stops extended to Airolo, though.)

On the stormy day, another "Re 10/10" (led by SBB Re 620 068 = Re 6/6 11668) reaches Faido station in an S-curve with another southbound intermodal freight train
After another wider valley section, beyond the station of Lavorgo, another large valley step with a 200 m drop starts. The first two kilometres of the Gola della Biaschina (Biaschina Gorge) are less dramatic. The railway and the road run directly above the Ticino river, while the elevated highway spoils the other side of the valley.

SBB Re 460 100 with a northbound IR will soon climb out of the gorge
A kilometre further, the gorge drops down, and the railway reaches the most spectacular section of the southern ramp: two successive loops above each other, with viaducts and spiral tunnels. To complete the jumble of engineering spectacles, the much steeper road curves through the middle while the highway passes high above on a large viaduct. Descending along the road riding the steep mountainside, the first sight is on the middle level, at the bottom exit of the 1,509 m long upper spiral tunnel.

An SBB RABDe 500 on a southbound ICN service left the upper spiral tunnel above the gorge
After the road-overpass-cum-short-tunnel, the middle level continues on an embankment.

SBB (formerly Cisalpino) ETR 470 0x9 "Insubrico" is visibly tilting both ways into the S-curve as it recedes towards the lower spiral tunnel on a southbound EC service
The class of the tilting train on the above photo is one infamously plagued by technical problems, and indeed the trains were replaced by locomotive-pulled trains at least once each day I was there (one is shown on the first photo in part one). It happened on my day of arrival in Switzerland, too, then causing a 20-minute cascading delay affecting the trains I rode too. The trains used to be operated by the "Cisalpino" joint venture of SBB and Trenitalia, which in 2009 was dissolved and the trains were divided between the partners upon failure to rein in the problems, now SBB wants to retire theirs next year.
Back to the middle level of the double spiral, the road continues down in a serpentine curve around a picturesque hamlet, from where the top level of the railway is visible: a 111 m viaduct between the upper spiral tunnel and another tunnel.

SBB Re 420 132 (Re 4/4II 11132) descends on the middle level with a southbound IR
After the second, 1,547 m long spiral tunnel, the line switches to the southern valley side again. From there, all three levels are perfectly visible (also see above the fold) – and I did manage to capture a moment when there were trains on all three levels.

SBB Re 420 121 (Re 4/4II 11121) with a southbound IR exits the lower spiral tunnel and crosses the river at the lowest level, the end of a northbound IR on the middle level can barely be seen in the shadow of the highway viaduct, while DB 185 136 and a sister (both Bombardier TRAXX F140AC1) with their southbound mixed freight reached the viaduct on the upper level and will soon meet the IR within the upper spiral tunnel
Downriver from Biaschina Gorge, the line runs along the edge of the valley bottom.

Seen from the hamlet at the middle level of the double spiral, quadruple-voltage loco 186 109 (Bombardier F140MS) of Swiss private operator railCare is about to enter the lower spiral tunnel with a northbound intermodal freight train
On the edge of the next town, Giornico, there is a last cross-over to the northern side of the Ticino, and nearby is the steepest section of the entire line (27‰), but this section is less photogenic due to noise barriers.
After Bodio the line passes over the southern portal of the Gotthard Base Tunnel. I don't have a photo of it, but it isn't any more impressive than the northern portal shown in part one. Here the new line runs along the already flat bottom of the valley while the old line finishes its descent, crosses the major tributary Brenno on yet another viaduct, then turns south and arrives at the bottom station of the southern ramp: Biasca (293 m above the sea). This is also the end-point of frequent all-stopper passenger trains from the south, yet all station facilities (including toilets) were closed by the early evening.

Above: looking north as SBB RABe 524 007 (a Stadler FLIRT) waits for departure as an S10 service (which crosses the border into Italy) in the rapid-transit-style TiLo regional passenger service network, with various shunter locomotives on standby
Below: SBB RABDe 500 008 "Vincenzo Vela" and 022 "Expo.02" recede towards Bellinzona on a southbound ICN service
In one additional diary, I'll show what runs above the Gotthard Tunnel.
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