TransLink 101: What’s interlining?
TransLink 101: What’s interlining?
We’re going back to basics again with TransLink 101—explaining TransLink and its operations!
Interlining combines two or more independent routes into one operational schedule. By doing so, we eliminate extended periods of down time where a bus would just be parked and out of service.
Katherine McCune, Manager of Service Planning at Coast Mountain Bus Company, tells us bus routes are interlined for several reasons, but one of the main reasons is scheduling efficiencies.
“It helps us minimize the footprint we use in the downtown core, for example,” she says. “A bus can arrive downtown as one route and sit very just a very few minutes and then leave as the next scheduled trip on another route.
Examples of interlined routes around the region include the 110, 144 and 116; the 403 and 480; and 601, 602, 603 and 604.
Wouldn’t it be most efficient if the buses ran nonstop – an operator drives his route and immediately goes back the opposite direction? Katherine tells us that is not the case.
“If you run buses nonstop you would no longer have a fixed schedule,” she says. “Customers require a schedule so they can make transfers to other services and have some idea of bus arrival at their stop. Without a schedule customers would not know when to expect the buses.”
One of the challenges of interlining is incidents on one leg of the bus’s journey can impact the service on the other end, Katherine notes.
“An accident on Hastings Street slowing the 135 could result in a delay in service on the 145, for example. However, with any serious incident our Transit Communications centre gets involved and makes adjustments on the road to ensure that service interruptions are minimal.”
Interlining also gives our operators some variety in their work, so they are not constantly driving the same roadways all the time!
Author: Allen Tung
So knowing that 96 B line runs 40 foot buses on weekends and that it shares a common terminus with 319, 323, 324, 325, 335, 341 and 375 during that time period, why is it not interlined?
Hi Juan. I asked CMBC and they say even though the 96 B-Line shares the same terminus with the 319, 323, 324, 325, 335, 341 and 375, the biggest consideration when determining which routes are interlined is the headway. Headway is the time interval between successive vehicles operating on the same route in the same direction. Interlining works best when the routes interlined have similar headways. The 96 B-Line runs at such a frequent headway and the other services are not, so it’s not a good candidate to interline.
CMBC also does have articulated buses that run on the 96 B-Line during the weekend since they become the N19 NightBus. Given the corridor this route serves, if there are special events that take place we like to be able to put the artics on if required. For example, for holiday service (which is Sunday service or a modified Sunday service) on Boxing Day, we will have the artics out as we anticipate large crowds for shopping.
Would you be able to provide a full listing of interlined routes throughout the system?
Separate but similar question: is TransLink still planning to merge the 015 and 050 under a single route number? I’m surprised this hasn’t happened yet.
Hi Eric B and Eric Doherty. Unfortunately, CMBC does not have an actively maintain a list of interlined routes published since it changes with every sheet change. Interlining works best when the routes interlined have similar headways, so interlines change as we adjust headways.
As for the 015 and 050, CMBC says it is currently being looked at.
Thanks Buzzer! This is important information for people who want to understand how our public transit system operates. I second Eric B’s request for a list of all interlined bus routes. I particularly want to know if the #20 is one of them.
Hi Juan, Eric, and Eric: Thanks for your questions! I’ll check in with Coast Mountain Bus Company to see if we can get the answers to your questions.
@ Eric Doherty: I believe the #20 is no longer interlined with another route, but I remember it used to be interlined with the #3 a while back. The only trolley routes that are currently interlined are the #5 and #6.
According to the sheet, there are very few interlinings for the 20 with the other routes. There exist a 32, one with the 009, and a 002.
Additionally, the N20 is interlined with the 41.
I know of these other ones around the system:
004-014
005-006-(010)
026-027-028-029
341-364-375-595
253-254
097-143-160-701-(N9)
402-430-(N10)
312-319-640
250-257
135-145-(N35)-(N19)
104-410-401-402-407-(N10)
240-246
241-247
210-211-212
099-N17
All Orion express routes in Richmond (mainly 351-601)
All conventional services in Surrey except the express routes
All conventional services in PoCo
It all comes dowb to the base of operations for the bus. E.g. we will never see a 340-410 interline because 340 runs from surrey and 410 runs from Richmond, even though they both touch 22nd street station. Special cases can occur. Since BTC-North needs help with the 135, some PCTC buses heading back to the base for the off peak hours run as a 135 rather than heading straight back. Same with the 49 with few trips coming off the 41 in the PM.
Thanks for getting us all answers so quickly Allen! I actually have a question, although it’s not exactly related.
Why wasn’t the N17 changed to the N14 when the 17 route was split and the 14 created? It certainly has an interesting history behind the route numbers, but I find it’s confusing that the N17 doesn’t go down Oak, but to UBC. Any chance this will be changed to reduce potential customer confusion?
Hi Jordan. Here’s the answer to your question from CMBC!
For example, we have a C19 route and we haven’t heard of people being confused with the 19 service. ;)
The best way to learn about interlined routes is to analyse bus schedules. Pretty much every bus route is interlined with some other. The only exceptions are the very frequent routes (B-Lines), specialized routes (620, 480, 555), and the trolley routes (except the 5/6).
Take any burnaby route for example: the 144, 116, 106, 125, 130… all terminate at metrotown, and use the same bus (nova bus) from the same depot (BTC). Routes such as the 125 which operate very sporadically and therefore must be interlined. Same scenario in Surrey, North Van, and Coquitlam.
Kyle: 125 doesn’t terminate at metrotown and most trips use Artics from BTC. Burnaby’s artics do not serve metrotown.
Talking about university, There is a run in the PM rush where the 49 interlines with the 106 and 144. It is a PM rush hour trip. It starts from UBC as a 049, goes up to SFU and back as a 144, then finishes as a 106 to New West. Therefore, this is the only bus that visits SFU and UBC in the same run.
About interlining:
The GTFS (bus schedule for google) indicates that:
When you do a query on Google, interlining is detected.
The tanslink trip planner recognize also when interlining occurs, but doesn’t provide the correct amount of Transfer ( example on Cambie at 12Ave to Granvlle Island
Other interlining can occurs more rarely: such as some buses doing the following trip 403 then 480 then 49.
again the GTFS shedule indicates that when it happens (in fact it indicate the schedule of each and every vehicle).
Do you want to overload customers with such pecular information?
Keeping information simple and understandable is probably better…
Thanks Allen!
I totally get they are often different routes, I just assumed there was always an effort to number them similarly. Such as in your examples the N19 follows the same route as the 19, but then continuing along to Surrey. Or the N9 being somewhat of a continuation of the 9 (and the 99 before the Millennium Line was built). Or even the N24 somewhat replicating the 240’s routes. In light of all this I just assumed it wouldn’t be too difficult to rename the service for clarity. I feel most people understand that “C” denotes community shuttle that are there own routes while “N” denotes night service that typically follows their corresponding numbered route.
Although, if I can digress, the “C” denotation is a bit useless now that some routes use both vehicle types, and perhaps everything should be give a regular route number. It’s not like the “C” denotes a special type of service/frequency, unlike the “N” which one can easily understand provides a late night service (typically) on the corresponding route number.
Anyways just my two cents. Keep us the good work :)
Hi Jordan. I’m guessing it would have been quite an expenditure too – to change all of the bus stops from N17 to N14. If you like, you can make that suggestion official by registering it with Customer Relations at http://mfb.translink.ca. :)
You’re right that we sometimes use conventional buses on community shuttle routes and community shuttle buses on conventional bus routes. Last year, we ran an ‘Ask TransLink‘ series giving the Buzzer readers an opportunity to ask us questions! One of them was about community shuttle numbering. Here’s what Mary Reimer, one of our transit planners, said at the time:
Jordan raised a legitimate question. :)
When the N17 began service in 2003, it was the NightBus version of the 17, which at that time ran between UBC and Downtown (then continuing on to Marpole Loop).
But when the 17 UBC became the 14 UBC in 2011, the N17 did not follow suit, when it would have been logical to do so.
Especially since the 6/N6, 8/N8, 9/N9, 10/N10, 15/N15, 19/N19, 20/N20, and 22/N22 bear some resemblance to each other (as do the 135/N35 and 242/N24). It would seem that the NightBus route numbers were deliberately chosen so as to aid in wayfinding.
So now you have the curious situation that the 17 goes via Oak to Marpole, while the N17 goes via Broadway and 10th to UBC.
But it’s all old history now…
Sorry, Allen, your new comment had not yet been posted when I wrote mine.
I feel like the interlining would be relatively easy to determine based off the GTFS data, bout one has to make the distinction between a true interline as opposed to a single tripper. Also, due to the level of complexity with the interlines, some areas are just considered one large interlined region, such as Surrey, as Kyle brought up. In Surrey, I know that sometimes a single unit will run a 319, 321, 323, 324, 325, 337, 502, and so on. So I suppose the deeper you dig into the question of interlining, the more confusing and intricate it becomes.
I suppose though there are a few routes who just happily keep to themselves. The 33, 620 are good examples of this, but then there are also routes that are mainly on their own, barring one or two trippers, such as the 394 or the 503 (maybe, haven’t seen the block breakdown for that yet). Anyways, long story short, the interlining is very complicated, and the deeper you go, the more complicated it gets.
A question or two I do have for the wonderful planners at CMBC: Could we be provided with a list of the linegroups and the lines that run under them? Some of them are more simple, like the 601 linegroup (351, 601), but others are more convoluted, like the 321 linegroup. I’ve always wondered if it is a catchall linegroup for Surrey, or if busses change their linegroup during the day (although I highly doubt this)
Second: How do the GTFS blocks line up against the linegroup numbering system? For instance, I might be on a bus out of Bridgeport that’s running 601008, but the block as described by GTFS is perhaps 1337423. Is there a reason these are different, and why the GTFS blocks aren’t named in a similar manner to the linegroup identifiers?
Thanks a bunch!!
With regards to the N17/17 numbering:
The original numbering scheme for any bus travelling on a numbered avenue in Vancouver City was to correspond with the said avenue, ie: 4 FOURTH, 9 BROADWAY, 10 TENTH, 25 KING EDWARD, 41 FORTY FIRST, 49 FORTY NINTH. Then during the mid 80s in perpetration for the SkyTrain feeder route adjustments, the transit agency decided that a uniform # for both directions was better, along with denoting the destination as opposed to the route on the signage. When the 17 OAK (which still uses the route name, not the dest.) interlined with the 10 UBC, someone in charge decided it would be more consistent to renumber the 10 TENTH-UBC to the 17 TENTH-UBC…… even though the two routes were essentially not related at all seeing as how they routed through downtown. The whole point of number consistency was to keep buses travelling on the same street using the same number, but instead the result is confusion in both customer’s and planner’s intentions. And this brings us to the N17 UBC…Beware of the 16 Fourth-UBC when it gets interlined with the 16 29th Ave Stn. LOL