Date: 201508
Local time of day: 1201-1800
Location: BOS.Airport, MA
Flight conditions: VMC
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Tower BOS
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion; Situational Awareness; Time Pressure
Anomaly: Deviation / Discrepancy - Procedural FAR; Ground Event / Encounter Other / Unknown; Ground Incursion Runway
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Took Evasive Action
Contributing factors: Procedure; Environment - Non Weather Related; Airport
Primary problem: Airport

Narrative: Landing Runway 4R in BOS FO flying. Briefed a left turn off the runway to hold short of Runway 4L. I expected the FO to exit the runway at Taxiway 'Y' or 'N3' as we were at a landing weight of 13;8000 LBS. FO landed smoothly and then braked more aggressively than I expected and turned off at high speed Taxiway 'Y'. We transferred control of the aircraft once clear of the runway. I remained heads up at all times as I continued to slow the aircraft on the high speed taxiway. I observed no signage or lighting indicating that we were approaching Runway 33R at an acute angle until I was a very short distance to the hold short line painted on Taxiway Y for Runway 33R. I brought the aircraft to an immediate and controlled full stop. The nose gear of our aircraft remained short of the hold short line for the runway but a small portion of the nose of the aircraft extended over the line; Runway 33R was not an active runway and is typically used for turning off of 4R upon landing at BOS with ATC often initiating the turn off. I had never exited Runway 4R in BOS on to this taxiway before. I observed no signage or lighting identifying the converging runway ahead until I saw the hold short line. This may be due to the acute angle at which you approach the runway from this taxi way. We were subsequently cleared onto the taxiway by the tower to hold short of 4L. Tower frequency was busy as we exited 4R which may have prevented ATC from instructing us to taxi on to 33R to hold short or 4L.This is the only high speed taxiway off of runway 4R in BOS where you encounter a runway other than 4L. There was a lack of signage and/or lighting warning the pilot that they are approaching a runway ahead at an acute angle other than the hold short line. The sun angle also contributed to this situation as it made seeing the hold short line difficult until you were almost directly on top of the hold short line. I was not mentally prepared to exit the runway at this taxiway and my situational awareness was not what it should have been. The addition of visible signage and/or lighting alerting the pilot of the intersecting runway at this location would be a major improvement especially due to the acute angle that you approach the runway that makes it difficult to identify Runway 33R.




Synopsis: A B737-800 landed on BOS Runway 4R and exited at Taxiway Y but incurred Runway 33R because they did not see a hold short or other markings for that Runway.