Three-Door Electric ISBs for NUS: Zhongtong N12

A new piece of the puzzle has been unveiled for the electrification of the ISB network, as a 3-door variant of the Zhongtong N12 has been confirmed for NUS. These buses will add on to the BYD B12 fleet and slowly replace the aging 2-door diesel Volvo B9Ls, forming the new generation of 3-door electric ISBs.

2-door variants of the Zhongtong N12 have been operating in NUS since end-September, but two of the three were released to Sentosa in end-November. It is now increasingly likely that the 2-door variants were a temporary deployment, as the Campus Services promotional materials depicted a fleet of 3-door (not 2-door) buses with both Zhongtong and BYD designs. It was confirmed that only 10 BYD B12s were bought, of which 6 were for NUS. Thus, 3-door Zhongtong N12s will likely make up the balance of the electric buses at NUS, with 25 purchased for the NUS ISB.

One unit of the 3-door Zhongtong N12 was spotted parking in NUS in late December – PD679G, followed by other units such as PD554H and PD705P. Just like all other electric citybuses at NUS, the bus features a colour-coded EDS, PIDS and charging ports. It is also equipped with safety features such as a 360-degree camera and ADAS.

On the offside, the 3-door Zhongtong N12 looks visually identical to its 2-door sibling… unless you’re someone who pays attention to wheels like me. The 3-door variant of the Zhongtong N12 uses ZF axles with a convex “flowery” shape for the front hub, also found on the BYD B12 and the ADL Enviro500.

In contrast, the 2-door variant uses axles from Yangzhou Dongsheng (YDA), with a concave appearance featuring a circle of dots that vaguely resembles MAN axles.

I find it doesn’t look as nice, though, as it looks like something is missing. The ZF axle looks more solid somehow.

The rear of the bus is also very similar, but there is now a circular hatch on the rear for the main switch, and the third brake light is positioned higher than on the 2-door buses.

On the nearside, obviously, the third door is clearly visible. I’ve said enough about the benefits of a third door, so I won’t go on further. Do excuse the awkward lighting and editing as I didn’t stick around for long.

And from the rear, charging ports and vents near the doors. One difference is noticeable here – the side marker lights have a chrome surround not found on the 2-door variants. It gives the bus a slightly more premium feel.

On the inside of the 3-door Zhongtong N12, seven seats present in their 2-door siblings are gone to make way for the door: the back row of 5 seats, and the two seats on the nearside where the door would be. So the total seating capacity is 22, and the standing capacity should be 66 like the BYD B12. There is a step at the rear, higher than in the BYD, but the edge is lined with rubber to mitigate the impact should passengers fall on it.

Compared to the 2-door batch, there are some improvements:

• The interior PIS now uses untinted glass like the BYD B12, ensuring that the service numbers are visible; the 2-door batch was delivered with orange-tinted PIS panels which impacted the visibility.
• The glass panels separating the seating and standing areas are now larger, extending all the way to the stanchion poles without leaving a gap.
• The interior number plate is now mounted in the centre of the bus instead of the left side, which makes for better visibility without the plate being blocked by stanchion poles.
• The lower edge of the PIDS screen is wrapped with a yellow and black strip for visibility like in the BYD B12s.

These are visible in the comparison here, with 2-door PD728Z above and 3-door PD705P below.

More units of the 3-door Zhongtong N12 should be delivered to NUS in the coming weeks. Let’s see when they debut!